Order Code RL32948
Air Quality Issues and Animal Agriculture:
A Primer
Updated January 28, 2008
Claudia Copeland
Specialist in Resources and Environmental Policy
Resources, Science, and Industry Division

Air Quality Issues and Animal Agriculture: A Primer
Summary
From an environmental quality standpoint, much of the public and policy
interest in animal agriculture has focused on impacts on water resources, because
animal waste, if not properly managed, can harm water quality through surface
runoff, direct discharges, spills, and leaching into soil and groundwater. A more
recent issue is the contribution of emissions from animal feeding operations (AFO),
enterprises where animals are raised in confinement, to air pollution. This report
provides background on the latter issue. It will be updated as warranted.
AFOs can affect air quality through emissions of gases such as ammonia and
hydrogen sulfide, particulate matter, volatile organic compounds, hazardous air
pollutants, and odor. These pollutants and compounds have a number of
environmental and human health effects.
Agricultural operations have been treated differently from other businesses
under numerous federal and state laws. Some environmental laws specifically
exempt agriculture from regulatory provisions, and some are designed so that farms
escape most, if not all, of the regulatory impact. The primary regulatory focus on
environmental impacts has occurred under the Clean Water Act. In addition, AFOs
that emit large quantities of air pollutants may be subject to Clean Air Act regulation.
Some livestock operations also may be regulated under the release reporting
requirements of the Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA) and the Emergency Planning and Community Right-to-
Know Act (EPCRA). Questions about the applicability of these laws to livestock and
poultry operations have been controversial and have drawn congressional attention.
Enforcement of federal environmental laws requires accurate measurement of
emissions to determine whether regulated pollutants are emitted in quantities that
exceed specified thresholds. Two reports by the National Research Council
evaluated the current scientific knowledge base and approaches for estimating air
emissions from AFOs as a guide for future management and regulatory efforts.
Stakeholders may find little agreement on these issues, with the exception of
agreeing on a need for research to estimate, measure, and characterize emissions, and
to develop and evaluate technologies to mitigate and control emissions.
In an effort to collect scientifically credible data on air emissions, in January
2005 the Environmental Protection Agency (EPA) announced a plan negotiated with
segments of the animal agriculture industry. Called the Air Compliance Agreement,
it is intended to produce air quality monitoring data on AFO emissions, while at the
same time protecting participants through a “safe harbor” from liability under certain
provisions of federal environmental laws. Issues related to this agreement, which has
been controversial among environmental advocates, state and local air quality
officials, and some industry groups, are discussed separately in CRS Report
RL32947, Air Quality Issues and Animal Agriculture: EPA’s Air Compliance
Agreement
, by Claudia Copeland.

Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Air Emissions from Livestock and Poultry: Sources and Impacts . . . . . . . . . . . . . 2
Health and Environmental Impacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Control Strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Environmental Statutes and Regulation of Animal Feeding Operations . . . . . . . . 7
Clean Water Act . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Clean Air Act . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
CAA Regulation in California . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Other States’ Air Quality Regulatory Activities . . . . . . . . . . . . . . . . . 16
CERCLA and EPCRA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Enforcement Against AFOs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Congressional Interest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
National Research Council Reports on Air Emissions from AFOs . . . . . . . . . . 22
The Role of USDA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Research Priorities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
List of Figures
Figure 1. Fate and Transport of Air Emissions Associated with Animal
Feeding Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
List of Tables
Table 1. Potential Importance of AFO Emissions at Different Spatial Scales . . . 5
Table 2. CAA Classification of Substances in AFO Emissions . . . . . . . . . . . . . 11

Air Quality Issues and Animal Agriculture:
A Primer
Introduction
Animal agriculture is a $100 billion per year industry in the United States.
Livestock and poultry are raised on an estimated 1.3 million farms throughout the
nation. About 238,000 of these farms are considered animal feeding operations
(AFO) — agriculture enterprises where animals are kept and raised in confinement.
An estimated 95% of these are small businesses: most AFOs raise fewer than 300
animals. Very large AFOs, housing 300 or more animals such as cows (or equivalent
numbers of other animal species), are defined as concentrated animal feeding
operations, or CAFOs. For more than two decades, organizational changes within
the industry to enhance economic efficiency have resulted in larger confined
production facilities that often are geographically concentrated. Increased facility
size, greater numbers of animals being raised at large feedlots, and regional
concentration of livestock and poultry operations have, in turn, given rise to concerns
over the management of animal wastes from these facilities and potential impacts on
environmental quality.
From an environmental quality standpoint, much of the public and policy
interest in animal agriculture has focused on impacts on water resources, because
animal waste, if not properly managed, can adversely impact water quality through
surface runoff and erosion, direct discharges to surface waters, spills and other dry-
weather discharges, and leaching into soil and groundwater. However, animal feeding
operations can also result in emissions to the air of particles and gases such as
ammonia, hydrogen sulfide, and volatile organic chemicals (VOC). At issue today
are questions about AFOs’ contribution to total air pollution and corresponding
ecological and possible public health effects. Resolving those questions is hindered
by a lack of adequate, accurate, scientifically credible data on air emissions from
AFOs, data that are needed to gauge possible adverse impacts and subsequent
implementation of control measures.
This report provides background on these issues.1 It first reviews the types of
air emissions from livestock and poultry operations and their human health and
environmental impacts. It then discusses provisions of several federal laws
concerned with environmental impacts, beginning with the Clean Water Act, because
1 This report focuses on the animal production segment of agriculture. Other types of
production agriculture also can generate air emissions, such as land preparation and crop
harvest activities, prescribed burning, and other farming practices, or emissions associated
with storage and use of mobile source fuels and operation of farm vehicles, engines, and
equipment. While some of these types of emissions may contribute to air quality problems,
especially in agriculture-dominated regions, they are outside the scope of this report.

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protecting water resources has been the primary regulatory focus regarding livestock
and animal operations. The Environmental Protection Agency (EPA) has authority
to address AFO air emissions under several laws — the Clean Air Act; the
Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA, or Superfund); and the Emergency Planning and Community Right-to-
Know Act (EPCRA) — which are discussed next. Questions about the applicability
of these laws to livestock and poultry operations have been controversial in several
arenas and have drawn congressional attention. Studies by the National Research
Council concerning air emissions are reviewed, as are relevant activities of the states
and the U.S. Department of Agriculture. Finally, the report identifies a number of
key research questions needed to characterize and evaluate animal agriculture
emissions.
In January 2005, EPA announced a plan called the Air Compliance Agreement
that would produce air quality monitoring data on animal agriculture emissions from
a small number of farms, while at the same time protecting all participants (including
farms where no monitoring takes place) through a “safe harbor” from liability under
certain provisions of federal environmental laws. Some industry sectors involved in
negotiating this agreement, notably pork and egg producers, strongly support it, but
other industry groups that were not involved in the discussions have concerns and
reservations. State and local air quality officials and environmental groups oppose
the agreement. Issues related to the Air Compliance Agreement are discussed
separately in CRS Report RL32947, Air Quality Issues and Animal Agriculture:
EPA’s Air Compliance Agreement
, by Claudia Copeland.
Air Emissions from Livestock and Poultry:
Sources and Impacts
AFOs can affect air quality through emissions of gases (ammonia and hydrogen
sulfide), particulate matter (PM), volatile organic compounds (VOC), hazardous air
pollutants, microorganisms, and odor. AFOs also produce gases (carbon dioxide and
methane) that are associated with climate change. The generation rates of odor,
manure, gases, particulates, and other constituents vary with weather, time, animal
species, type of housing, manure handling system, feed type, and management system
(storage, handling, and stabilization).
Emission sources include barns, feedlot surfaces, manure storage and treatment
units, silage piles, animal composting structures, and other smaller sources, but air
emissions come mostly from the microbial breakdown of manure stored in pits or
lagoons and spread on fields. Each emission source will have a different profile of
substances emitted, with rates that fluctuate through the day and the year. The
sources, fate, and transport of AFO emissions are illustrated in Figure 1.
Health and Environmental Impacts
Pollutants associated with AFOs have a number of environmental and human
health impacts. Most of the concern with possible health effects focuses on


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ammonia, hydrogen sulfide, and particulate matter, while major ecological effects are
associated with ammonia, particulates, methane, and oxides of nitrogen.2
Figure 1. Fate and Transport of Air Emissions
Associated with Animal Feeding Operations
Source: The University of Iowa and The University of Iowa Study Group, Iowa Concentrated Animal
Feeding Operations Air Quality Study, Final Report
, 2002, p. 87.
The nitrogen in animal manure can be converted to ammonia (NH ) by a
3
combination of processes. Ammonia released from the surface of liquid manure
storage structures rapidly adheres to particles in the air, due to its cohesive properties,
thus contributing to the formation of ambient particulate matter, specifically
ammonium nitrate and ammonium sulfate. These particles form to a varying degree
in the presence of ammonia and oxides of nitrogen or sulfur (see below). Once
emitted, ammonia also is re-deposited back to earth in rainfall that can harm surface
waters and aquatic life in lakes and streams. Ammonia aerosols in rainfall contribute
to oxygen depletion of aquatic systems and excessive growth of algae, as well as
acidification of the environment. It is estimated that emissions from animal waste
account for about one-half of the total natural and anthropogenic ammonia emitted
in the United States annually. Ammonia has a strong, sharp, characteristic odor that
disperses rapidly in the air. Health effects at low concentrations include eye, nose
and throat irritation; exposure at very high short-term concentrations can be lethal.
Particles are highly complex in size, physical properties, and composition. For
regulatory purposes, airborne particulate matter (PM) is commonly considered as
coarse particles (those less than 10 microns in diameter, referred to as PM ), or fine
10
particles, those less than 2.5 microns in diameter (referred to as PM ). Agriculture
2.5
is a major direct source of PM , which is essentially dust raised from unpaved roads,
10
2 The following discussion is drawn primarily from National Research Council, Air
Emissions from Animal Feeding Operations, Current Knowledge, Future Needs
, 2003, pp.
65-71 (hereafter cited as NRC 2003 AFO Report); and David R. Schmidt et al., National
Center for Manure and Animal Waste Management, North Carolina State University, Air
Quality and Emissions from Livestock and Poultry Production/Waste Management Systems
,
August 12, 2002.

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grain mills or storage facilities, feeding equipment, and particles generated in other
mechanical processes. In contrast, PM is a different class of particles, resulting
2.5
more from evaporation and atmospheric chemical processes than direct emissions.
Fine particles are formed in the atmosphere through the interaction of gases such as
sulfur oxides, nitrogen oxides, and VOC.
AFOs can contribute directly to particulate matter through several mechanisms,
including animal activity, animal housing ventilation units, and particles of mineral
and organic material from soil and manure that adhere to air molecules. As described
above, particulate matter can contribute indirectly to fine particle formation by
emissions of ammonia, nitrogen oxides, and hydrogen sulfide, which are converted
to aerosols through reactions in the atmosphere. Particle formation is highly
dependent on atmospheric temperature, humidity, concentrations of the precursor
compounds, and other factors, so the particle formation is variable and difficult to
predict. Particles of differing sizes have been linked to health effects. Larger
particles tend to be deposited in the upper airways of the respiratory tract, whereas
small particles have both health and environmental effects: they can be deposited in
the smallest airways in the lungs and, while still airborne, also play an important role
in formation of regional haze. Populations with long-term exposure to heavier loads
of particles have higher rates of mortality from major cardiovascular diseases, as well
as increased rates of morbidity. The primary environmental and ecological effects
of particles are related to haze and decreased visibility, which is caused by the
suspended aerosols that both absorb and scatter light.
Hydrogen sulfide (H S) is a colorless gas with a strong and generally
2
objectionable rotten egg odor. It is produced in anaerobic (oxygen-deprived)
environments from the microbial reduction of sulfate in water and the decomposition
of sulfur-containing organic matter in manure. Acute human health effects include
respiratory and cardiovascular irritation, as well as headaches. H S may have local
2
effects of concern — especially odor — and may contribute to the atmospheric sulfur
burden of regions with a high density of AFOs, but few other sources.
Methane and nitrous oxide are known to contribute to global warming. An
estimated one-half of global methane comes from manmade sources, of which
agriculture is the largest source, with livestock production being a major component
within the sector. EPA estimates that 25% of the nation’s methane emissions come
from livestock. Agricultural methane is produced by ruminant animals, but also is
emitted during microbial degradation of organic matter under anaerobic conditions.
Nitrous oxide forms via the microbial processes of nitrification and denitrification.
In the United States, animal waste accounts for about 6% of nitrous oxide emissions.
Many of the complaints about AFOs are generated by odor. Odor from AFOs
is not caused by a single substance, but is rather the result of a large number of
contributing compounds, including ammonia, VOCs, and hydrogen sulfide. As
classes of compounds, odor and VOCs can be considered together. VOCs (also
referred to as reactive organic compounds, or ROG) vaporize easily at room
temperature and include a large number of constituents, such as volatile fatty acids,
sulfides, amines, alcohols, hydrocarbons, and halocarbons. In terms of their health
and environmental effects, some VOCs may irritate the skin, eyes, nose, and throat.
They also can be precursors to the formation of PM and ozone (smog).
2.5

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Adverse effects of ozone include lung damage and exacerbated respiratory
disease, as well as diminished visibility. Ozone in the troposphere, the lowest layer
of the atmosphere which is closest to the Earth, has both natural and anthropogenic
sources. It can damage forests, crops, and manmade materials, and harm respiratory
tissue through inhalation. Ozone that occurs naturally at ground-level is generally
at low concentrations that are not believed to threaten human health or the
environment. Ozone that is a byproduct of human activity is formed through the
interaction of sunlight with VOCs, nitrogen oxides, and other substances and adds
to the total atmospheric burden of the pollutant.
Effects of these pollutants occur on a variety of scales, as shown in Table 1.
Table 1. Potential Importance of AFO Emissions
at Different Spatial Scales
Global,
national, and
Local (property line
Primary effects of
Emissions
regional
or nearest dwelling)
concern
NH (ammonia)
Atmospheric deposition,
3
Major
Minor
haze
N O (nitrous oxide)
Significant
Insignificant
Global climate change
2
NO (the sum of
x
Haze, atmospheric
nitric oxide and
Significant
Minor
deposition, smog
nitrogen dioxide)
CH (methane)
Significant
Insignificant
Global climate change
4
VOCs (volatile
Insignificant
Minor
Quality of human life
organic compounds)
H S (hydrogen
2
Insignificant
Significant
Quality of human life
sulfide)
PM (coarse
10
Insignificant
Significant
Haze
particulate matter)
PM (fine
2.5
Insignificant
Significant
Health, haze
particulate matter)
Odor
Insignificant
Major
Quality of human life
Source: National Research Council, Air Emissions from Animal Feeding Operations, Current
Knowledge, Future Needs
, 2003, Table ES-1, p. 5. Rank order from high to low importance is major,
significant, minor, and insignificant. Emissions from non-AFO sources may have different rankings.
For example, VOCs and NO play important roles in the formation of tropospheric ozone, however,
x
the role of AFOs is likely to be insignificant compared to other sources.
Control Strategies
Manure management varies widely across animal species, region, and farm type,
depending on climate, soil productivity, farm size, and other factors. Systems and
strategies now in wide use by farmers are those that have proved the most cost-
effective and reliable at achieving their design objectives. Land application has been

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and remains the predominant method for disposing of manure and recycling its
nutrient and organic content. For the most part, design objectives for managing
manure do not include minimization of emissions of ammonia, methane or other
gaseous compounds, but rather focus on odor and dust control, avoidance of direct
discharge to surface water, and land application at rates that are beneficial to growing
crops.3
As noted above, emissions of odors, gases, and dust from livestock production
facilities arise from buildings, manure storage, and land application. Eliminating
emissions from one of these sources will likely not eliminate emissions entirely, as
control technologies often address only one of the three sources. Many of the
available technologies reduce emissions; none eliminates them.4 Some technologies
have been evaluated to the point of demonstrating efficacy, but most have not been
evaluated systematically.
Emissions from buildings can be reduced by inhibiting contaminant generation,
or by capturing and treating the air as it leaves the building (e.g., by using biofilters
to treat ventilation air, or wet or dry scrubbing of air as it passes through evaporative
pads before release). Frequent manure removal is one of the best ways of reducing
contaminant generation within the building. Other methods that can be used inside
buildings include using bedded solid manure (i.e., manure mixed with bedding that
creates a solid stack of material), chemical additives on animal litter, and diet
manipulation.
There are four general types of manure storage: deep pits, outdoor slurry storage,
anaerobic lagoons, and solid stacks. Outdoor storage is the most apparent source of
odors. Controls that have been shown to be effective when managed properly include
various types of covers (permeable and impermeable, natural such as straw or
cornstalks, and synthetic). Techniques to manipulate the manure to minimize
emissions also exist but have certain limitations. For example, separating solids from
liquid manure reduces the load on anaerobic lagoons, but also creates a second waste
stream to manage which may be detrimental to overall air quality. Proper aeration
will eliminate odors from outdoor storage, but it is expensive in a liquid system.
Anaerobic digesters reduce odors, but they are also not economically feasible.5
Emission control during land application is best done by direct injection of
liquid manure below the soil surface. Solid manure is generally less odorous than
liquid, but because it cannot be injected, rapid incorporation into the soil by plowing
or similar techniques is the best method to minimize odors.
While many treatment technologies are available that may be important in
mitigating emissions, the effectiveness of most of them is not well quantified.
3 NRC 2003 AFO Report, pp. 46-47.
4 Iowa State University and The University of Iowa Study Group, Iowa Concentrated
Animal Feeding Operations Air Quality Study, Final Report
, February 2002, p. 203.
(Hereafter cited as Iowa CAFO Air Quality Study.)
5 Ibid., p. 207.

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Extensive research programs are underway in the United States and Europe, and
many options of varying cost and effectiveness are being evaluated. Livestock
emission mitigation research is being performed by the University of California at
Davis, California State University Fresno, Purdue University, Texas A&M
University, and others, and information on available control measures and strategies
for agricultural sources of air pollution is being presented.6 Experts believe that cost,
increased management requirements, and a lack of economic or regulatory incentives
to encourage or require their use are the primary reasons that more poultry and
livestock producers have not adopted technologies to reduce emissions.7
Environmental Statutes and Regulation of
Animal Feeding Operations
The animal sector of agriculture has undergone major changes in the last several
decades, a fact that has drawn the attention of policymakers and the public. In the
United States there are an estimated 238,000 animal feeding operations where
livestock and poultry are confined, reared, and fed, according to the U.S. Department
of Agriculture’s 1997 Census of Agriculture.
Organizational changes within the industry to enhance economic efficiency have
resulted in larger confined production facilities that often are geographically
concentrated.8 The driving forces behind structural change in livestock and poultry
production are no different than those that affect many other industries: technological
innovation and economies of scale.9 From 1982 to 1997, the total number of U.S.
operations with confined livestock fell by 27%. At the same time, the number of
animals raised at large feedlots (generally confining 300 animals or more) increased
by 88%, and the number of large feedlots increased by more than 50%.10 The
traditional image of small farms, located in isolated, rural locales, has given way to
very large farming operations, some on the scale of industrial activities. Increased
facility size and regional concentration of livestock and poultry operations have, in
turn, given rise to concerns over the management of animal wastes from these
facilities and potential impacts on environmental quality.
6 For example, the California Air Pollution Control Officers Association maintains a website
to assist agricultural operators, local air districts, and others with information on air
pollution reduction techniques. See [http://www.capcoa.org/agclearinghouse.shtml].
7 Ibid., p. 209.
8 For additional information, see CRS Report RL33325, Livestock Marketing and
Competition Issues
, by Geoffrey S. Becker.
9 Marc Ribaudo et. al, U.S. Department of Agriculture, Economic Research Service,
Manure Management for Water Quality: Costs to Animal Feeding Operations of Applying
Manure Nutrients to Land
, June 2003, Agricultural Economic Report 824, 87 pp.
10 U.S. Department of Agriculture, Natural Resources Conservation Service, Manure
Nutrients Relative to the Capacity of Cropland and Pastureland to Assimilate Nutrients:
Spatial and Temporal Trends for the United States
, Publication no. nps00-0579, December
2000, p. 18. (Hereafter cited as USDA 2000 Manure Nutrients report.)

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Agricultural operations often have been treated differently from other types of
businesses under numerous federal and state laws. In the area of environmental
policy, one observer noted that agriculture is “virtually unregulated by the expansive
body of environmental law that has developed in the United States in the past 30
years.”11 Some laws specifically exempt agriculture from regulatory provisions, and
others are structured in such a way that farms escape most, if not all, of the regulatory
impact. The Clean Water Act (CWA), for example, expressly exempts most
agricultural operations from the law’s requirements, while under the Clean Air Act
(CAA), most agricultural sources escape that law’s regulatory programs because the
majority of them do not meet the CAA’s minimum emission quantity thresholds.
Moreover, in implementing environmental laws, federal and state regulators have
traditionally focused most effort on controlling the largest and most visible sources
of pollution to the water, air, and land — factories, waste treatment plants, motor
vehicles — rather than smaller and more dispersed sources such as farms.
Nevertheless, certain large animal feeding operations are subject to
environmental regulation. The primary regulatory focus on environmental impacts
has been on protecting water resources and has occurred under the Clean Water Act.
In addition, facilities that emit large quantities of air pollutants may be regulated
under the Clean Air Act. Some livestock operations may also be subject to the
release reporting requirements of the Comprehensive Environmental Response,
Compensation, and Liability Act (the Superfund law) and the Emergency Planning
and Community Right-to-Know Act. The following sections describe relevant
provisions of these laws.
Clean Water Act
The Clean Water Act (CWA, 33 U.S.C. §§1251-1387) provides one exception
to policies that generally exempt agricultural activities — and specifically the
livestock industry — from environmental rules. The law protects water quality by
a combination of ambient water quality standards established by states, limits on
effluent discharges, and permits.12 The regulatory structure of the CWA
distinguishes between point sources (e.g., manufacturing and other industrial
facilities which are regulated by discharge permits) and nonpoint sources (pollution
that occurs in conjunction with surface erosion of soil by water and surface runoff of
rainfall or snowmelt from diffuse areas such as farm and ranch land). Most
agricultural activities are considered to be nonpoint sources, since they do not
discharge wastes from pipes, outfalls, or similar conveyances. Pollution from
nonpoint sources is generally governed by state water quality planning provisions of
the act.
However, the CWA defines large animal feeding operations that meet a specific
regulatory threshold number of animals (termed concentrated animal feeding
11 J. B. Ruhl, “Farms, Their Environmental Harms, and Environmental Law,” Ecology Law
Quarterly
, vol. 27, no. 2 (2000), p. 265.
12 For additional information on the Clean Water Act, see CRS Report RL30798,
Environmental Laws: Summaries of Statutes Administered by the Environmental Protection
Agency
, by Susan Fletcher, coordinator.

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operations (or CAFO); they are a small percentage of all animal feeding operations)
as point sources and treats CAFOs in a manner similar to other industrial sources of
pollution. They are subject to the act’s prohibition against discharging pollutants into
waters of the United States without a permit. In 2003, EPA revised regulations that
were first promulgated in the 1970s defining the term CAFO for purposes of permit
requirements and specifying effluent limitations on pollutant discharges from
regulated feedlots.
These regulations are intended to address the concern that animal waste, if not
properly managed, can adversely impact the environment through several possible
pathways, including surface runoff and erosion, direct discharges to surface waters,
spills and other dry-weather discharges, leaching into soil and groundwater, and
releases to air (including subsequent deposition back to land and surface waters).
The primary pollutants associated with animal wastes are nutrients (particularly
nitrogen and phosphorus), organic matter, solids, pathogens, and odorous/volatile
compounds. Data collected for the EPA’s 2000 National Water Quality Inventory
identify agriculture as the leading contributor to water quality impairments in rivers
and lakes. Animal feeding operations are only a subset of the agriculture category,
but 29 states specifically identified animal feeding operations as contributing to water
quality impairment.13
The 2003 clean water rule applies to approximately 15,500 of the largest animal
feeding operations that confine cattle, dairy cows, swine, sheep, chickens, laying
hens, and turkeys, or about 6.5% of all animal confinement facilities in the United
States. The rule details requirements for permits, annual reports, and development
of plans for handling manure and wastewater. The rule contains a performance
standard which prohibits discharges from regulated CAFOs except in the event of
wastewater or manure overflows or runoff from an exceptional 25-year, 24-hour
rainfall event. Parts of the rule are intended to control land application of animal
manure and wastewater.14 In June 2006, EPA proposed revisions to the 2003 rule,
in response to a federal court ruling that had upheld major parts of the regulation,
vacated other parts, and remanded still other parts to EPA for clarification. EPA
estimates that under the proposed rule about 14,100 CAFOs will be required to
obtain permits. The proposal also provides for greater public participation in
connection with nutrient management plans, requiring that they be subject to public
notice and review and be included as enforceable elements of a permit. Under the
2003 rule, CAFOs were to obtain permits by February 2006 and to develop and
implement nutrient management plans by December 2006. As a result of the federal
court ruling, EPA pushed back the deadlines for permits and nutrient plans to July
31, 2007. However, in May 2007, EPA announced that it is still considering
comments on the 2006 proposal and does not expect to complete work on a final rule
until 2008. Thus, EPA extended the July 31, 2007, compliance deadline until
February 27, 2009 — giving certain livestock operators another 19 months to obtain
13 U.S. Environmental Protection Agency, National Water Quality Inventory, 2000 Report,
August 2002, EPA-841-R-02-001, 1 vol.
14 For additional information, see CRS Report RL31851, Animal Waste and Water Quality:
EPA Regulation of Concentrated Animal Feeding Operations (CAFOs)
, by Claudia
Copeland.

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discharge permits and to develop and implement manure management plans. The
compliance deadline extension will not apply to new livestock operations or to
existing CAFOs that were required to obtain permits prior to the 2003 rule.15
Scientists recognize that actions taken to mitigate harmful water quality impacts
of managing animal waste can have implications for air quality, in complex ways that
are not perfectly understood. Environmental policies do not always account for
interactions between media. For example, to meet water quality goals, lagoons are
commonly used to store and treat manure waste from swine and other operations.
These storage systems volatilize nitrogen, thereby reducing its concentration in
lagoon effluent. But the volatilized nitrogen compounds escape into the air, creating
odors, contributing to fine particulates (haze), and potentially hastening global
climate change.16
Clean Air Act
The Clean Air Act (CAA, 42 U.S.C. §§7401-7671q) provides a complex and
comprehensive framework for regulating stationary and mobile sources of air
pollution.17 The law emphasizes controlling “major sources” that emit more than
threshold quantities of regulated pollutants. Air emissions from farms typically do
not exceed the specified thresholds, thus they generally escape most CAA regulatory
programs. However, livestock producers and other agricultural sources are not
exempt from the statute, and for any whose emissions meet statutory or regulatory
definitions of “major,” provisions of the act could apply.
Under the CAA framework, EPA designates criteria air pollutants that may
reasonably be anticipated to endanger public health or welfare, and then establishes
nationally uniform ambient air quality standards for those pollutants (NAAQS).18
EPA has identified six criteria pollutants, two of which (particulate matter and
nitrogen dioxide) are directly associated with AFO emissions. In addition, AFOs and
other sources emit a number of substances (VOCs and nitrogen oxide compounds)
which are precursors of ozone, another criteria pollutant. The CAA also regulates
hazardous air pollutants (HAP). HAPs are identified in a statutory list that can be
modified by EPA regulation; EPA currently regulates 188 HAPs, including volatile
organic compounds (VOC) which are emitted by livestock facilities. Precursors of
ozone (reactive VOCs) and PM (ammonia), both emitted by livestock facilities, are
2.5
15 For additional information, see CRS Report RL33656, Animal Waste and Water Quality:
EPA’s Response to the “Waterkeeper Alliance” Court Decision on Regulation of CAFOs.

16 Marcel Aillery, Noel Gollehon, Robert Johansson, Jonathan Kaplan, Nigel Key, Marc
Ribaudo, Managing Manure to Improve Air and Water Quality, U.S. Department of
Agriculture, Economic Research Report 9, September 2005.
17 For additional information on the Clean Air Act, see CRS Report RL30798,
Environmental Laws: Summaries of Statutes Administered by the Environmental Protection
Agency
, by Susan Fletcher, coordinator.
18 Under the act, EPA establishes primary ambient air quality standards at a level sufficient
to protect the public health. EPA also is authorized to establish secondary ambient air
quality standards designed to protect the public welfare.

CRS-11
regulated air pollutants, even though they are not listed as criteria pollutants or HAPs.
(See Table 2.)
States play an important role in carrying out CAA provisions and assuring that
state air quality meets federal air quality standards. The State Implementation Plan
(SIP), prepared by the state (or local) air pollution control agency, translates national
ambient standards into emission limitations and other control measures that govern
individual sources of air pollution; the SIP is enforceable as both state and federal
law. The CAA details the basic content of SIPs: enforceable emission limitations,
other control measures, monitoring requirements, and schedules for compliance. The
provisions of the SIP govern individual facilities through two types of state
permitting programs. The preconstruction permit applies to major new sources or
major modifications of an existing source, and it describes proposed air pollution
abatement systems, allowable emission rates, and other requirements. In addition,
most major stationary sources are required to obtain operating permits which specify
each source’s emission limitations and standards, compliance schedule, reporting
requirements, and other conditions.
Table 2. CAA Classification of Substances in AFO Emissions
Criteria
Hazardous air
Regulated air
Substance
pollutant
pollutant
pollutant
Ammonia a
X
Nitrogen oxides
X
X
VOCs b
X
X
Hydrogen sulfide c
X
PM d
X
X
10
PM
X
X
2.5
Odor e
X
Source: National Research Council, Air Emissions From Animal Feeding Operations, Current
Knowledge, Future Needs
, 2003, table 1-1, p. 16.
a. Ammonia is not a criteria pollutant but is a precursor for secondary PM , which is a criteria
2.5
pollutant.
b. Some but not all VOCs are listed as hazardous air pollutants. VOCs contribute to the formation
of ozone, a criteria pollutant.
c. Hydrogen sulfide is not listed as a criteria pollutant or a hazardous air pollutant. However, it is a
regulated pollutant because it is listed as having a New Source Performance Standard which
EPA establishes for facilities that contribute significantly to air pollution.
d. Prior to 1987, particulate matter (PM) was a criteria pollutant and regulated as total suspended
particulate (TSP). Currently, the PM fractions listed as criteria pollutants are PM and PM .
10
2.5
e. Odor is a regulated pollutant in some states.
The CAA threshold determination of whether a source — including a livestock
or poultry operation — is subject to these requirements depends on whether it is

CRS-12
defined as “major.” That definition differs based on the region in which the source
is located and whether that region is attaining and maintaining national ambient air
standards. The act classifies nonattainment areas based on the extent to which the
NAAQs is exceeded, and it specifically creates five classes of ozone nonattainment
(from least to most polluted: marginal, moderate, serious, severe, and extreme).
More stringent control requirements are imposed in areas with worse pollution.
Generally, a major source is a stationary source that emits, or has potential to emit,
100 tons per year or more of any pollutant. However, regulated sources of HAPs that
emit more than 10 tons per year of an individual hazardous pollutant, or sources in
the most serious nonattainment areas that emit as little as 10 tons per year of VOCs
or NO are defined as major sources and would be subject to these CAA
x,
requirements.
A state’s SIP provisions must be at least as stringent as federal requirements, but
beyond the core CAA framework, states have latitude in adopting requirements to
achieve national ambient air quality standards. States, for example, may regulate
additional categories of sources or may define major sources more stringently than
do federal programs.
Most agricultural operations are believed to be minor sources of air pollution,
and few have been required to comply with the act’s permit requirements. Some
environmental advocates have argued that many large livestock facilities emit more
than 100 tons per year of regulated pollutants (especially ammonia) and should be
regulated as major sources under federal law. However, federal and state officials
generally have placed a low priority on regulating agricultural sources, and, further,
a lack of adequate air quality monitoring data hampers the ability of regulators to
answer key questions. Agricultural air pollution has become more of an issue in
some parts of the country as EPA implements the 1997 NAAQS for particulates,
which EPA revised in September 2006,19 and as nonattainment areas look to reduce
pollutants from more sources as they strive to come into attainment. As discussed
previously, emissions of ammonia and several other AFO pollutants are precursors
that transform in the atmosphere to form secondary particulate matter. Aside from
ammonia, other agriculture pollutants include dust that contributes to PM , diesel
10
emissions from farm equipment, and emissions from specialized activities such as
crop burning.20
A 2004 lawsuit brought in federal court by environmentalists argued that
feedlots must be regulated under the Clean Air Act and must obtain a CAA “permit
to construct” under provisions of the Idaho SIP. The company, intending to construct
a large feedlot, had argued that the SIP did not require a permit for key pollutants
from agricultural sources, including ammonia and hydrogen sulfide. In September
2004, the court ruled that the state’s plan did not allow such exemptions, indicating
that any agricultural facility in the state with sufficient emissions levels would have
to obtain a permit. The case was settled early in 2005 when the parties to the lawsuit
19 For additional information,, see CRS Report RL33254, Air Quality: EPA’s 2006 Changes
to the Particulate Matter (PM) Standard
, by Robert Esworthy and James E. McCarthy.
20 For additional information, see CRS Report 97-670, Agriculture and EPA’s New Air
Quality Standards for Ozone and Particulates
, by James E. McCarthy and Jeffrey A. Zinn.

CRS-13
agreed to request that the Idaho Department of Environmental Quality conduct a
rulemaking to establish a process for CAA permitting of dairies in the state (Idaho
Conservation League v. Adrian Boer
, D.Id.,Civ. No. 1:04-cv-00250-BLW, February
1, 2005). Industry officials say the case has limited implications, because it refers
specifically to the Idaho SIP, but environmentalists involved in the case believe it
could have significance nationally because of the mutual agreement by the parties on
emissions factors for ammonia that trigger CAA thresholds for dairies. In response
to this case, in June 2006 Idaho finalized a requirement that dairies and other CAFOs
obtain air quality permits if they emit 100 tons or more of ammonia per year. The
new rule makes Idaho the first state to regulate ammonia emissions from CAFOs.
In calculating emissions to determine major sources, fugitive emissions are not
counted; however, they do count for purposes of demonstrating attainment with
NAAQS. Fugitive emissions are defined in regulation as “those emissions which
could not reasonably pass through a stack, chimney, vent or other functionally
equivalent opening” (40 CFR §51.165(a)(1)(ix)). EPA has issued a number of
interpretive memoranda and guidance documents discussing how fugitive emissions
should be accounted for in evaluating such industries as landfills, printing, and paint
manufacturing. No such guidance with respect to animal confinement systems has
been issued, but some groups, who believe that agricultural air pollution should be
more vigorously controlled, have in the past expressed concern that EPA might make
a determination that emissions from waste lagoons and barns are fugitive, thus
excluding those types of AFO emissions from applicable CAA requirements. In a
2003 letter to EPA, state and local air program administrators said that such a policy,
if pursued, would create inequities in CAA application between similar operations
in some sectors but not others.
Since barns and lagoons are the dominant sources of emissions from the CAFO
industry, such a policy would exempt most agricultural operations from many
provisions of the Clean Air Act. The result would be an evisceration of states’
and localities’ ability to address air quality problems emanating from agricultural
operations.21
CAA Regulation in California. Some of the interest in agriculture’s impact
on air quality derives from events in California and that state’s progress in
implementing the permit and SIP provisions of the Clean Air Act. The state’s air
pollution problems are diverse and, in some areas, severe. Throughout the state,
emission controls have become increasingly more stringent on currently regulated
sources of air pollution, such as factories and cars. State officials believe that, to
meet state and federally mandated requirements to improve air quality, emissions
from all air pollution sources must be reduced, whether they are large or small,
industrial or agricultural.
With regard to agriculture, air quality improvement efforts have focused
primarily on two regions which represent California’s most challenging air quality
problems for ozone and particulate matter pollution. The South Coast (Los Angeles)
21 Lloyd L. Eagan (President of State and Territorial Air Pollution Program Administrators)
and Ellen Garvey (President of Association of Local Air Pollution Control Officials), letter
to Christine Todd Whitman (EPA Administrator), April 7, 2003, p. 2.

CRS-14
Air Basin and the San Joaquin Valley Air Basin are designated in extreme
nonattainment for the federal health-based 1-hour standard for ozone. In addition,
the South Coast Basin and the San Joaquin Valley Basin are designated in severe and
serious nonattainment, respectively, for the more protective federal 8-hour ozone
standard. In these two areas, all sources of air pollution produce air quality impacts
and have some level of significance, and virtually all emission sources, even very
small ones, are regulated. Both areas have large concentrations of confined animal
feeding operations; agriculture is the San Joaquin Valley Basin’s most important
industry and a significant source of its air emissions. Thus, agricultural sources have
been a particular focus of efforts to implement the federal and state laws in both
regions.22
For more than 30 years, California law specifically exempted existing major
livestock production or equipment used in crop growing from all environmental
permitting requirements. In 1994, EPA notified the state that the agriculture
exemption was a defect in the state’s clean air program that prevented California
from fully regulating all air pollution sources. That notification and settlement of a
lawsuit by citizen groups seeking to force EPA to impose air pollution controls on
California’s agriculture industry finally led EPA in October 2002 to withdraw federal
approval of the state’s program. Pursuant to the Clean Air Act, EPA was then
required to implement a federal program while the state addressed the cited
deficiencies. Following that action, and during the time it temporarily had
responsibility for the California program, EPA evaluated ways to administer the law,
while minimizing significant new permitting requirements on thousands of existing
agricultural sources in the state. A major concern was recognition that there was
insufficient scientific information about agricultural air emissions to immediately
issue permits to sources or mandate pollution control requirements.
EPA considered various regulatory options, but did not actually issue any
permits in California before its responsibility for the state program ended in August
2003. The state re-assumed responsibility after the legislature enacted a measure
(California SB 700) that removed the long-standing exemption for agriculture and
set timelines for existing facilities to apply for clean air permits and install control
technologies. SB 700 regulates crop growers, dairies, poultry farms, cattle ranches,
food-processing operations, and other agriculture-related businesses in the state. As
of January 1, 2004, it made these sources subject to air quality permitting and
specified emission mitigation requirements. Deadlines and requirements differ,
depending on the size of facilities, level of emissions, and the attainment status of the
region where the source is located.
The state and its local air quality management districts (in California, the state
sets overall rules and policies, and 35 local agencies have primary day-to-day
responsibility) are now implementing SB 700. The law mandated that the state Air
Resources Board review scientific information and adopt a definition of large
confined animal facilities by July 2005; that information is now being used by local
air districts to begin issuing permits to facilities and adopting various regulations to
22 Ten areas of the state have been designated in nonattainment for the one-hour federal
ozone standard.

CRS-15
control emissions. Under SB 700, the district rules must require facilities to obtain
permits and to reduce emissions to the extent feasible. For severe and extreme ozone
nonattainment areas, the law requires best available retrofit control technology
(BARCT). In moderate and serious areas, regulated facilities will need to use
reasonably available control technology (RACT). In federal ozone attainment areas
where air quality problems are less significant, districts must adopt a rule requiring
existing large confined animal facilities to reduce air contaminants to the extent
feasible unless the district makes a finding that such facilities will not contribute to
a violation of any state or federal standard. Regulated facilities must prepare
emission mitigation plans and must comply with them by July 1, 2008.
The definition of “regulated facility” developed by the state board seeks to
include the majority of emissions, or animals, which are in the larger livestock
facilities in the state. By focusing on large facilities and excluding smaller farms,
dairies and other operations, the board expects to obtain the most air quality benefit
while regulating the fewest number of facilities. Under the approach approved by the
board in June 2005, agricultural operations in areas designated in nonattainment for
the federal 1-hour ozone standard will be defined as large confined animal facilities
based on specified numbers of animals at the facility (for example, facilities with
1,000 or more milk-producing cows or 650,000 chickens at broiler chicken
operations) and will be required to obtain air quality permits. In areas with less
significant air quality problems — those designated as in attainment for the federal
one-hour ozone standard — thresholds are twice as high (e.g., 2,000 milk-producing
cows or 1.3 million broiler chickens).23 In addition, the state board is working with
local air districts, university researchers, and others to develop and evaluate research
on emissions factors from livestock operations to be used by facilities that are
required to obtain air permits. Affected industries are closely watching these
research studies and the standards being adopted by local air districts.
Even before the state board defined which existing facilities face new
requirements, some local air quality control districts had moved ahead with
permitting and emission reduction requirements. For example, the San Joaquin
Valley district adopted rules to reduce PM emissions from general crop-based
agricultural operations and dairies with 500 or more cows, and in the South Coast
district, dairies with 50 or more cows are required to reduce emissions. Industry
contends that the state board should have first established how much pollution comes
from livestock operations before any permitting requirements were implemented, but
the local districts interpreted SB 700 as requiring permits by January 1, 2005. The
local districts have attempted to provide flexibility, but the overall situation has
created substantial confusion for the farm community in California. Districts also
have adopted additional rules more recently. For example, the San Joaquin Valley
district adopted a rule in June 2006 to curb VOC emissions from dairies and other
CAFOs. Farmers in the state have resisted efforts to implement federal and state
laws to regulate emissions from agriculture. Some in industry contend that
agriculture emissions are not major sources of pollution and that any regulation
23 State of California, California Environmental Protection Agency, Air Resources Board,
Staff Report: Initial Statement of Reasons for Rulemaking, Public Hearing to Consider the
Large Confined Animal Facility Definition
, May 6, 2005, 102 pp.

CRS-16
should await completion of federal and state studies that are examining the industry’s
contribution to air pollution.
While California SB700 focuses on existing agricultural sources, by lifting the
long-standing exemption for such operations from the state Health & Safety Code,
new and modified agriculture sources in the state also became subject to permit and
regulatory requirements of the California State Implementation Plan (SIP). New or
modified sources located in nonattainment areas which may emit air pollution must
obtain New Source Review permits that require installation of best available control
technology (BACT) and require purchase of “offsets” or “emission reduction credits”
from other sources in the same nonattainment area, in a relation determined by the
severity of the air pollution problem. Local district rules implement these federal and
state requirements. For example, San Joaquin Valley District Rule 2201 requires a
new or modified stationary source, including agriculture sources, to install BACT
when the potential to emit VOC exceeds 2 pounds per day and to purchase offsets for
VOC when the source’s potential to emit exceeds 10 tons per year.
As agriculture operations continue to locate in areas of the state that already are
highly industrialized by agriculture, their compliance with these environmental
requirements is being scrutinized. For example, a large dairy under construction in
Tulare County (San Joaquin Valley) has been sued by local citizen groups for Clean
Air Act violations stemming from constructing a major stationary source without a
New Source Review permit.24
Other States’ Air Quality Regulatory Activities. In terms of geographic
impact, every state has agricultural operations in which animals are raised in
confinement, according to the U.S. Department of Agriculture. States with high
livestock populations, and with significant numbers of large operations (i.e., with
more than 300 animal units), include several West Coast, Southwest, and Northwest
states (Washington, Oregon, California and Arizona); the whole of the Midwest,
from the Dakotas, Minnesota and Wisconsin south through Texas; sweeping across
the southeast to the coastal states of Georgia, the Carolinas, Virginia, Maryland, and
Pennsylvania; and north through New York and Vermont.25
The issue of evaluating and managing the health and environmental impacts of
emissions from animal agriculture facilities has largely been left up to states. Air
quality has not been the driving force behind state government action on AFOs, but
has emerged out of long-standing concern to protect water resources. Several states
have recognized a need to regulate air emissions from agricultural operations, but
many states have not yet directly adopted or enacted programs affecting AFO
emissions.
State programs, under statutes and regulations, both implement and supplement
federal CAA requirements. That is, in some cases, state programs have been adopted
to ensure state compliance with requirements of the federal law and to implement
24 Association of Irritated Residents, et al, v. Fred Schakel Dairy, E.D. Ca., No. 05-707, filed
June 1, 2005.
25 USDA 2000 Manure Nutrients report, pp. 28-29.

CRS-17
SIPs, such as facility permits that apply to construction and operation of livestock
operations. In other cases, states have enacted more comprehensive laws and
regulations calling for air emission testing and monitoring, manure management to
abate pollutant emissions, inspections, and testing. Some states have regulatory
programs or ambient air standards for odor and/or certain AFO pollutants, such as
hydrogen sulfide, for which no NAAQS apply. In states with significant animal
production, facility management statutes often govern construction and operation of
AFOs, primarily for purposes of protecting water quality, with incidental provisions
for air quality. For example, facility management statutes often contain setback
requirements for confinement buildings and waste impoundments that may help to
reduce air emissions by avoiding or minimizing odor nuisances.
A recent survey of seven states26 identified a number of measures to govern air
emissions from livestock facilities, but no comprehensive regulatory systems. States
have used varied techniques to control air emissions from AFOs. State programs set
emission limits, require use of best management practices, and impose other pre-
operational and operational requirements. Hydrogen sulfide and odor emissions from
AFOs have received significant attention, but there is little or no standardization of
approach. For example:
! Minnesota requires feedlots and manure storage areas to acquire
construction and operating permits and also requires air emission
plans for large livestock facilities. The state has adopted an ambient
air quality standard for hydrogen sulfide which applies to emissions
from AFOs as well as other sources.
! Iowa also has adopted a health effects-based ambient air quality
standard for hydrogen sulfide that will be used in a three-year AFO
field study to measure levels of H S, ammonia and odor to determine
2
if material adverse health effects exist.
! Missouri regulations set odor emission limitations and require large
AFOs to submit odor control plans. In addition, the state’s CAA
permit program includes operational requirements for AFOs to
prevent air pollution. Missouri’s CAA contains a hydrogen sulfide
emission standard that does not refer to AFOs or other agricultural
operations specifically, nor does it exempt AFOs. Missouri also has
an ambient acceptable level (AAL) for ammonia.
! In Texas, a consolidated program governs water and air quality
general permits. Its requirements control the emission of odors and
other air contaminants from AFOs, although its does not have a
specific air emission threshold for odors. Like Missouri, Texas has
a hydrogen sulfide emission standard that makes no specific
reference to, or exception for, animal agriculture.
26 Jody M. Endres and Margaret Rosso Grossman, “Air Emissions from Animal Feeding
Operations: Can State Rules Help?” Pennsylvania State Environmental Law Review, vol.
13, fall 2004, pp. 1-51.

CRS-18
! Illinois has implemented a facility statute that relies in part on
setback distances to control odor emissions. Like Missouri, Illinois
has established a numerical “objectionable odor nuisance” standard
(that is, when odor is detectable in ambient air adjacent to residential
or similar structures after dilution with a specific volume of odor-
free air) and has enforced the limitation against AFOs.
! Colorado water quality rules help to control air emissions through
provisions that govern the construction and operation of facilities
that treat animal wastes. A separate regulation establishes an odor
emissions standard for swine feeding operations and requires that
anaerobic waste impoundments be covered.
! North Carolina, like Colorado, has focused its regulatory efforts on
odor emissions from swine operations. All AFOs must use
management practices that control odors, and some swine operations
must submit odor management plans, although it does not require
control technology (e.g., covers) unless best management practices
fail. North Carolina does not have air emission standards for H S,
2
ammonia, or odor.
A separate survey done by the Nebraska Department of Environmental Quality
found that more than half of the states have standards for hydrogen sulfide. States
base standards on a variety of issues, including odor or nuisance, welfare effects, and
health effects. Consequently, standards vary considerably from as low as 0.7 parts
per billion (ppb) for a yearly average (New York) and 5 ppb averaged over 24 hours
(Pennsylvania), to standards based on nuisance, such as Minnesota’s 50 ppb not to
be exceeded for one-half hour twice per year and measured at the AFO property
line.27
CERCLA and EPCRA28
Both the Comprehensive Environmental Response, Compensation, and Liability
Act (CERCLA, or Superfund, 42 U.S.C. §§9601-9675) and the Emergency Planning
and Community Right-to-Know Act (EPCRA, 42 U.S.C. §§11001-11050) have
reporting requirements that are triggered when specified quantities of certain
substances are released to the environment, including ambient air.29 Both laws utilize
information disclosure in order to increase the information available to the
government and citizens about the sources and magnitude of chemical releases to the
environment. At issue today is how the reporting requirements and other provisions
of these laws apply to poultry and livestock operations.
27 Iowa CAFO Air Quality Study, p. 189.
28 For additional information, see CRS Report RL33691, Animal Waste and Hazardous
Substances: Current Laws and Legislative Issues
, by Claudia Copeland.
29 For additional information on CERCLA and EPCRA, see CRS Report RL30798,
Environmental Laws: Summaries of Statutes Administered by the Environmental Protection
Agency
, coordinated by Susan Fletcher.

CRS-19
Superfund authorizes programs to remediate uncontrolled or abandoned
hazardous waste sites and assigns liability for the associated costs of cleanup.
Section 103(a) of CERCLA requires that the person in charge of a facility (as defined
in Section 101(9)) that releases a “reportable quantity” of certain hazardous
substances must provide notification of the release to the National Response Center.
EPCRA establishes requirements for emergency planning and notification to
communities about storage and release of hazardous and toxic chemicals. Section
304(a)(1) of EPCRA requires the owner or operator of a facility (as defined in
Section 329(4)) to report to state and local authorities any releases greater than the
reportable quantity of substances deemed hazardous under Superfund or extremely
hazardous under EPCRA. Under Superfund, the term “release” (Section 101(22))
includes discharges of substances to water and land and emissions to the air from
“spilling, leaking, pumping, pouring, emitting, emptying, discharging, injection,
escaping, leaching, dumping, or disposing into the environment.” Under EPCRA,
the term “release” (Section 329(8)) includes emitting any hazardous chemical or
extremely hazardous substance into the environment. Superfund excludes the
“normal application of fertilizer” from the definition of release, and EPCRA excludes
from the definition of hazardous chemicals any substance “used in routine
agricultural operations or is a fertilizer held for sale by a retailer to the ultimate
customer.”
The Superfund definition of “hazardous substance” (Section 101(14)) triggers
reporting under both laws. Among the reportable substances released by livestock
facilities are hydrogen sulfide and ammonia. The reportable quantity for both of
these substances is 100 pounds per day, or 18.3 tons per year. Section 109 of
Superfund and Section 325 of EPCRA authorize EPA to assess civil penalties for
failure to report releases of hazardous substances that equal or exceed their reportable
quantities (up to $27,500 per day under CERCLA and $27,500 per violation under
EPCRA).
In addition to these reporting requirements, Superfund includes provisions
authorizing federal cleanup of releases of hazardous substances, pollutants, or
contaminants that may present an imminent and substantial danger to the public
health or welfare (Section 104) and imposing strict liability for cleanup and damages
to natural resources from releases of hazardous substances (Section 107). The
applicability of these provisions to animal agricultural sources and activities has
increasingly been receiving attention.
Enforcement Against AFOs. EPA has enforced the CERCLA/Superfund
and EPCRA reporting requirements against AFO release of hazardous air pollutants
in two cases. The first involved the nation’s second largest pork producer, Premium
Standard Farms (PSF) and Continental Grain Company. In November 2001, EPA
and the Department of Justice announced an agreement resolving numerous claims
against PSF concerning principally the Clean Water Act, but also the Clean Air Act,
CERCLA, and EPCRA. Among other actions under the settlement, PSF and
Continental were to monitor air emissions for PM, VOCs, H S, and ammonia, and
2
if monitoring levels exceed CAA thresholds for any regulated pollutant, the
companies would apply to the State of Missouri for any necessary CAA permits. The
companies also agreed to fund a $300,000 supplemental environmental project (SEP)

CRS-20
to reduce air emissions and odors from swine barns. More recently, in September
2006, the Department announced settlement of claims against Seaboard Foods, a
large pork producer with more than 200 farms in Oklahoma, Kansas, Texas, and
Colorado, and PIC USA, the former owner and operator of several Oklahoma farms
now operated by Seaboard. Like the earlier Premium Standard Farms case, the
government had brought complaints for violations of several environmental laws,
including failure to comply with the release reporting requirements of CERCLA and
EPCRA.
Both Superfund and EPCRA include citizen suit provisions that have been used
to sue poultry producers and swine operations for violations of the laws. In two
cases, environmental advocates claimed that AFO operators have failed to report
ammonia emissions, putting them in violation of CERCLA and EPCRA. In both
cases, federal courts have supported broad interpretation of key terms defining
applicability of the laws’ reporting requirements (Sierra Club v. Seaboard Farms
Inc.
, 387 F.3d 1167 (10th Cir. 2004) and Sierra Club v. Tyson Foods, Inc., 299
F.Supp. 2d 693 (W.D. Ky. 2003)).
EPA was not a party in either of these lawsuits. The U.S. Court of Appeals for
the 10th Circuit invited EPA to file an amicus brief in the Seaboard Farms case, in
order to clarify the government’s position on the issues, but EPA declined to do so
within the timeframe specified by the court.
Three other cases in federal courts, while not specifically dealing with reporting
violations and air emissions or what constitutes a “facility” for reporting purposes,
also have attracted attention, in part because they have raised the question of whether
animal wastes that contain phosphorus are hazardous substances that can create
cleanup and natural resource damage liability under Superfund. In 2003 a federal
court in Oklahoma held that phosphorus contained in poultry litter in the form of
phosphate is a hazardous substance under CERCLA and thus could subject poultry
litter releases to provisions of that law (City of Tulsa v. Tyson Foods, Inc., 258 F.
Supp. 2d 1263 (N.D. Okla. 2003)). This ruling was later vacated as part of a
settlement agreement, but some observers believe that the court’s reasoning may still
be persuasive with other courts. The second case, City of Waco v. Schouten (W.D.
Tex., No. W-04-CA-118, filed April 29, 2004), a suit by the city against 14 dairies
alleging various causes of action based on disposal of wastes from those operations,
was resolved by a settlement agreement early in 2006.
The third case, State of Oklahoma v. Tyson Foods, Inc. (N.D. Okla, No. 4:05-cv-
00329, filed June 13, 2005), is still pending. This suit, brought by the Oklahoma
Attorney General, asserts various claims based on the disposal of waste from 14
poultry operations in the Illinois River Watershed. The state principally seeks its past
and present response costs under CERCLA due to release of wastes from these
facilities and natural resource damages. The net result of these lawsuits is growing
concern by the agriculture community that other legal actions will be brought and that
the courts will continue to hold that the CERCLA and EPCRA reporting
requirements and other provisions apply to whole farm sites, thus potentially
exposing more of these operations to enforcement under federal law.

CRS-21
In 2005, a group of poultry producers petitioned EPA for an exemption from
EPCRA and CERCLA emergency release reporting requirements, arguing that
releases from poultry growing operations pose little or no risk to public health, while
reporting imposes an undue burden on the regulated community and government
responders.30
In December 2007, EPA issued a proposal in response to the poultry industry
petition.31 The proposal would exempt releases of hazardous substances to the air
(typically during digestion or decomposition) from animal waste at farms from the
notification requirements of CERCLA and EPCRA. The exemption would apply to
releases to the air from manure, digestive emissions, and urea, including animal
waste mixed with bedding, compost, and other specified materials. “Farm” is
defined in the proposal as an agricultural operation from which $1,000 or more of
agricultural products are sold annually (the same definition used by the Department
of Agriculture). EPA explained that the rule is justified because of the resource
burden to industry of complying with reporting requirements, since the agency cannot
foresee a situation where a response action would be taken as a result of notification
of releases of hazardous substances from animal waste at farms.32
The proposal is expected to draw significant public response during the
comment period, which closes March 27, 2008. While such a regulatory exemption
might satisfy many agriculture industry groups who seek a waiver or other means to
limit possible liability under CERCLA and EPCRA, environmental advocates and
others oppose the exemption, saying that emissions from animal wastes are not trivial
or benign. Critics note that the EPA proposal would exempt releases of ammonia,
as originally requested in the industry petition, plus hydrogen sulfide and all other
hazardous chemicals, such as nitrous oxide and volatile organic compounds. It also
would apply to all livestock operations, not just poultry farms. Some argue that an
exemption is premature, since EPA is moving forward with research on emissions
levels, which could be undermined by a regulatory exemption (see CRS Report
RL32947, Air Quality Issues and Animal Agriculture: EPA’s Air Compliance
Agreement
). State air quality officials have said that they oppose blanket regulatory
or legislative exemptions, and they recommended that if the agency considers any
action, it should only be a narrow exemption, such as one based on a size threshold
for farms.33
30 In 1998, EPA granted an administrative exemption from release reporting requirements
for certain radionuclide releases. EPA cited authority in CERCLA Sections 102(a), 103, and
115 for granting administrative reporting exemptions where “releases of hazardous
substances that pose little or no risk or to which a Federal response is infeasible or
inappropriate.” See 63 Federal Register 13461 (March 19, 1998).
31 U.S. Environmental Protection Agency, “CERCLA/EPCRA Administration Reporting
Exemption for Air Releases of Hazardous Substances from Animal Waste,” 72 Federal
Register
73700 (December 28, 2007).
32 Ibid., p. 73704.
33 National Association of Clean Air Agencies, letter to the Honorable Barbara Boxer,
chairman, Senate Environment and Public Works Committee, March 20, 2007.

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Congressional Interest. Congressional interest in these issues has been
apparent for some time. For example, in report language accompanying EPA’s
FY2006 appropriations, the House Appropriations Committee urged EPA to clarify
the reporting requirements of the two laws.34
The Committee continues to be concerned that unclear regulations, conflicting
court decisions, and inadequate scientific information are creating confusion
about the extent to which reporting requirements in [CERCLA] and [EPCRA]
cover emissions from poultry, dairy, or livestock operations. Producers want to
meet their environmental obligations but need clarification from the
Environmental Protection Agency on whether these laws apply to their
operations. The committee believes that an expeditious resolution of this matter
is warranted.
Specific legislative proposals also have been discussed. In the 109th Congress,
legislation was introduced that would have amended CERCLA to clarify that manure
is not a hazardous substance, pollutant, or contaminant under Superfund and that the
law’s notification requirements would not apply to releases of manure (H.R. 4341).
It was introduced the same day (November 15, 2005) that a House Energy and
Commerce subcommittee held a hearing on animal agriculture and Superfund. The
Subcommittee on Environment and Hazardous Materials heard from agriculture
industry witnesses who urged Congress to provide policy direction on the issue that
has resulted from recent and potential litigation. Other witnesses testified that the
reporting and notification requirements of CERCLA and EPCRA provide a safety net
of information, and that other environmental laws, such as the Clean Air Act, cannot
function in that manner. Related legislation was introduced in the Senate (S. 3681).
No further action occurred on either bill, but similar legislation has been introduced
in the 110th Congress (H.R. 1398 and S. 807). (For additional discussion, see CRS
Report RL33691, Animal Waste and Hazardous Substances: Current Laws and
Legislative Issues
.)
National Research Council Reports on
Air Emissions from AFOs

During the time that EPA was developing the revised Clean Water Act CAFO
rules that it promulgated in 2003 (discussed above), the issue of air emissions from
CAFOs received some attention. The Clean Water Act requires EPA to consider
non-water quality environmental impacts, such as air emissions, when it sets effluent
limitations and standards. EPA recognized that certain animal waste management
practices can either increase or decrease emissions of ammonia and/or hydrogen
sulfide and that some regulatory options intended to minimize water discharges (such
as anaerobic lagoons and waste storage ponds) have the potential to result in higher
air emissions than other options, due to volatilization of ammonia in the waste.
Likewise, emissions of nitrous oxide are liberated from land application of animal
34 U.S. Congress, House Committee on Appropriations, Report accompanying H.R. 2361,
Department of the Interior, Environment, and Related Agencies Appropriation Bill, 2006
,
H.Rept. 109-80, 109th Cong., 1st sess., p. 87.

CRS-23
waste on cropland when nitrogen applied to the soil undergoes nitrification and
denitrification.35 Some environmental groups had urged EPA to address or restrict
feedlot air emissions as part of the water quality rule. In the proposed rule and the
2003 final revised rule, EPA generally evaluated air emissions impacts of the rule,
but it said that insufficient data exist to fully analyze all possible compounds and the
significance of air emissions from feedlot operations.
In part because of this lack of information, in 2001 EPA asked the National
Research Council (NRC) of the National Academy of Sciences for a report evaluating
the current scientific knowledge base and approaches for estimating air emissions
from AFOs. EPA asked the NRC to identify critical short- and long-term research
needs and provide recommendations on the most promising science-based
approaches for estimating and measuring emissions. USDA joined EPA in the
request for the study. At the time, EPA was under a court order to issue the water
quality rules and hoped that the NRC report would help assure that rules aimed at
improving water quality would not have negative impacts on air emissions.
In an interim report released in 2002, the NRC responded to several of the EPA
questions.24 Nitrogen emissions from production areas are substantial, the committee
found, and control strategies aimed at decreasing emissions should be designed and
implemented now. It recommended developing improved approaches to estimating
and measuring emissions of key air pollutants from AFOs and initiating long-term
coordinated research by EPA and USDA with the goal of eliminating release of
undesirable air emissions. The committee said that implementation of feasible
management practices that are designed to decrease emissions, such as incorporating
manure into soil, should not be delayed while research on mitigation technologies
proceeds. This report focused particularly on the suitability of an approach for
estimating air emissions from AFOs presented in a 2001 draft EPA report. In that
report, EPA attempted to develop a set of model farms, based on manure
management systems typically used by large AFOs, and identify emissions factors
that could be associated with each element of the model farm. In the absence of
actual data from extensive monitoring, EPA hoped that emission factors could be
applied to model farms to estimate annual mass emissions.25
An emissions factor is a representative value that attempts to relate the quantity
of a pollutant released to the atmosphere with an activity associated with the release
of the pollutant. The emission factor approach is based on measuring emissions from
a set of defined AFOs to obtain an average emission per unit (per animal unit, or per
production unit process, such as manure storage piles and lagoons, stall areas, and
feed storage areas), then multiplying the emission factor by the number of units and
period of time (e.g., annually). The current method of estimating cow, chicken,
35 Nitrification and denitrification are biological processes that, respectively, oxidize
ammonia to nitric acid, nitrous acid, or any nitrate or nitrite; and reduce nitrates or nitrites
to nitrogen-containing gases.
24 National Research Council, The Scientific Basis for Estimating Air Emissions from Animal
Feeding Operations, Interim Report
(Washington, DC: National Academies Press, 2002).
25 U.S. Environmental Protection Agency, Emissions from Animal Feeding Operations
(Draft)
, EPA Contract No. 68-D6-0011, Washington, DC, August 15, 2001, 414 pp.

CRS-24
swine, or any other livestock animal emissions is generally expressed in terms of
emissions per head, per year. Using this method, facility emissions are directly
proportional to the number of animals at the facility.
The NRC recognized that direct measurements of air emissions at all AFOS are
not feasible. However, it found that the model farm construct described by EPA
cannot be supported because of weaknesses in the data needed to implement it, which
fail to consider variations in many factors (geography, climate, management
approaches) that could affect annual amounts and temporal patterns of emissions
from an individual AFO. Alternatively, the NRC recommended that EPA consider
a more complex process-based approach to focus on activities that determine the
movement of nutrients and other substances into, through, and out of each component
of the farm enterprise.
The NRC expanded on these recommendations in its final report, issued in
2003.26 Overall, it found that scientifically sound protocols for measuring air
concentrations, emission rates, and fates are needed for the elements, compounds,
and particulate matter associated with AFOs. Similarly, standardized methodology
for odor measurement should be developed in the United States, the NRC said. The
report noted that emission factor approaches should be broadened to integrate animal
and crop production systems both on and off the AFO (i.e., imported feeds and
exported manure) in order to represent the full environmental effects of animal
production systems. Such a systems analysis should include impacts of best
management practices (BMPs) aimed at mitigating AFO air emissions on other parts
of the entire system.
The Role of USDA

The U.S. Department of Agriculture (USDA) manages a diverse range of
programs involving food, forests, rural development, agricultural trade, and
conservation of natural resources. Several USDA agencies have conservation
responsibilities that may involve livestock and their environmental effects. For
example, the Natural Resources Conservation Service (NRCS) provides technical
assistance and information, as well as financial assistance, to landowners and
agricultural producers to implement conservation systems and practices, such as
developing Comprehensive Nutrient Management Plans to control AFO runoff.
The Agricultural Research Service (ARS) is the in-house research agency of
USDA and conducts a wide range of research activities. Among those related to
livestock production are national programs directed to air quality (focusing on
particulates, agriculturally emitted ammonia, and odor) and manure and by-product
utilization (focusing on nutrient management and atmospheric emissions). A second
USDA agency is the Cooperative State Research, Education, and Extension Service
(CSREES). Like ARS, CSREES has projects related to livestock production, such
as an animal waste management program aimed at educating producers and
increasing the use of best management practices through training for AFO operators.
26 NRC 2003 AFO Report.

CRS-25
USDA cooperates with EPA when issues concern both agriculture and the
environment. Notably, the two collaborated on a Unified National Strategy for
Animal Feeding Operations, issued in 1999, intended to minimize public health and
environmental impacts of runoff from AFOs. That strategy consisted of multiple
elements and was based on a national performance expectation that all AFO owners
and operators would develop and implement site-specific Comprehensive Nutrient
Management Plans by 2009 to protect water quality and public health.
The importance of relationships between air quality and agriculture has received
increased recognition at USDA in recent years. One direct result was enactment of
a provision in the 1996 Federal Agriculture Improvement and Reform Act (P.L. 104-
127), the farm bill, requiring USDA to create an Agricultural Air Quality Task Force.
One finding in Section 391 of the statute stated that USDA should lead efforts to
determine accurate measures of agriculture’s role in air pollution and in the
development of cost-effective approaches to reduce pollution. Several provisions of
the 2002 farm bill (the Farm Security and Rural Investment Act, P.L. 107-171)
specifically addressed air quality issues in the context of USDA conservation
programs.
The Agricultural Air Quality Task Force is an advisor to the Secretary of
Agriculture. Its chairman is the chief of the NRCS, and its members represent
USDA, EPA, industry, and basic and applied science. It is charged with ensuring
sound data quality and interpretation, so that policy recommendations made by
federal or state agencies to address air pollution problems related to agriculture are
based on accurate scientific findings, peer review, and economic feasibility.
In 2000, the task force issued a white paper on air quality and CAFOs. It
recommended a program of accelerated research, education, technology transfer,
technical training, and financial assistance to address CAFO air quality problems.
According to the white paper, current funding levels for air quality research are
“elusive” and cannot be separately identified from all animal waste-related research.
It recommended that USDA and EPA develop enhanced long-term funding packages
and programs for agricultural air quality research and technology transfer that
specifically address CAFOs. The task force recommended that at least $12.8 million
per year be spent by USDA (NRCS, ARS, and CSREES) for coordinated, integrated
research and technical assistance programs for animal agriculture air quality.27 In
FY2006, ARS supported four projects to assess emissions from beef cattle feedlots,
dairy operations and poultry operations and to evaluate swine wastewater treatment
systems. CSREES administers a National Research Initiative on Air Quality which
supports about a dozen projects on various topics intended to better understand the
environmental fate of agricultural atmospheric emissions, increase farm adoption of
best management practices to reduce agricultural emissions, and establish
scientifically sound emissions targets.
27 USDA Agricultural Air Quality Task Force, Air Quality Research and Technology
Transfer White Paper and Recommendations for Concentrated Animal Feeding Operations
,
July 19, 2000. (Hereafter cited as AAQTF CAFO White Paper.)

CRS-26
Research Priorities
In debates over controversial and complex public policy questions, stakeholders
who hold differing perspectives at times may find little common ground. Sometimes
the only point of agreement is the need for more and better research to resolve key
questions — and each side hopes that research findings will support its own
perspectives on the issues at hand. With regard to questions about AFO emissions
and the possible need to implement control strategies, there is little dispute about the
need for more research. Research on a wide range of topics currently is being
supported by federal agencies, a number of individual states, academic institutions,
and industry, but there is no apparent coordination or unified strategy. The
monitoring study that EPA proposes as part of the Air Compliance Agreement is
intended to answer some questions. However, in view of criticism of the study,
doubts exist about the study’s utility. Some critics of the Air Compliance Agreement
fault EPA for planning only to measure emissions, but not also using the monitoring
study as an opportunity to research mitigation techniques.
In its 2003 report, the National Research Council addressed these issues and
recommended “substantial research efforts in both the short term and the long term.”
Research in the short term (four to five years), the NRC said, can significantly
improve the capability of scientifically sound modeling approaches for measuring
and estimating air emissions, especially for process-based modeling that the NRC
recommends be developed by EPA and USDA. A long-term research program (20-
30 years) that encompasses overall impacts of animal production on the environment
can have substantial results in decreasing overall impacts on the environment, while
sustaining production at a high level. For the long term, coordinated research is
needed to determine which emissions are most harmful to the environment and
human health and to develop technologies to decrease their releases into the
environment28
Priority research needs identified by the NRC, USDA’s Agricultural Air Quality
Task Force,29 and others fall into two broad categories: fundamental research to
estimate, measure, and characterize emissions; and technology research (including
technology transfer).
! Foremost is the need to produce scientifically sound, standardized
methodology as a basis for measuring and estimating gaseous and
particulate emissions and odor, from AFOs on local, regional, and
national scales. The science for estimating air emissions from
individual AFOs should be strengthened, along with models to
understand the totality of AFO processes, including dispersion,
transformation, and deposition of emissions. This information is
needed in order to assess relationships between emissions, potential
health indicators, and candidate regulatory and management
programs.
28 NRC 2003 AFO Report, pp. 11, 174-175.
29 AAQTF CAFO White Paper, p. 5.

CRS-27
! A related concern is that much more needs to be understood about
community-level impacts from exposure to AFO emissions.
Occupational health studies have documented adverse health effects
among AFO workers, such as acute and chronic respiratory diseases,
but experts agree that occupational health risks cannot be
extrapolated to community health risks. Peer reviewed studies of
health impacts on residents in the vicinity of livestock operations are
limited. These findings support a conclusion that AFO air emissions
constitute a public health hazard, deserving of public health
precautions as well as larger, well controlled, population-based
studies to more fully ascertain adverse health outcomes and their
impact on community health.30
! With regard to technology, there is a need to develop standardized
measurement technologies for pollutants and odorous compounds
emitted by AFOs and effective, practical, and economically feasible
technologies to reduce and control odors and pollutants. Experts
believe that there is a need to develop and evaluate innovative
treatment processes for each of the major sources of AFO emissions,
confinement buildings, manure storage areas, and land application.
Research further should include programs to provide for transfer of
economically viable technologies to all producers.
In its 2003 report, the National Research Council observed that EPA and USDA
have not devoted the necessary technical or financial resources to estimate air
emissions and develop mitigation technologies, and it criticized both for failing to
address this deficiency in defining high-priority research programs. The report said,
“Each has pursued its regulatory and farm management programs under the
assumption that the best currently available information can be used to implement its
program goals.” It concluded that a change in research priorities in both agencies is
needed if air emissions are to be addressed with an adequate base of scientific
information.31
Congressional attention to the issues discussed in this report has been limited,
with the result that developments are proceeding largely by administrative and some
judicial actions, not through legislative policymaking. As described previously, one
aspect that has attracted some congressional interest is questions about the
applicability of Superfund and EPCRA to livestock and poultry operations. That
interest has been especially apparent in the context of appropriations legislation and,
more recently, in legislation to amend Superfund to clarify that manure is not a
hazardous substance (H.R. 4341 and S. 3681 in the 109th Congress; these bills were
not passed, but similar legislation — H.R. 1398 and S. 807 — has been introduced
in the 110th Congress). A House subcommittee held a hearing on these issues in
November 2005. Finally, there appears to be wide agreement among stakeholder
groups on the need for more research on a large number of related issues, but
30 Iowa CAFO Air Quality Study, p. 138.
31 NRC 2003 AFO Report, pp. 13, 153.

CRS-28
congressional interest in supporting or funding more federal participation in research
activities is unclear.