Order Code RS20531
Updated January 23, 2006
CRS Report for Congress
Received through the CRS Web
Noise Abatement and Control: An Overview
of Federal Standards and Regulations
David M. Bearden
Analyst in Environmental Policy
Resources, Science, and Industry Division
Summary
Noise is generally considered to be unwanted sound. Noise can be harmful or
merely irritating, depending on how loud it is and the degree of exposure. Constant or
repeated exposure to sounds of 90 decibels or higher can lead to hearing loss. Most
individuals are also sensitive to unwanted sounds above 65 decibels, and often perceive
such sounds as intrusive. To limit the public’s exposure to these sound levels, the
federal government sets and enforces uniform noise standards for aircraft and airports,
interstate motor carriers and railroads, workplace activities, medium- and heavy-duty
trucks, motorcycles and mopeds, portable air compressors, federal highway projects, and
federal housing projects. State and local governments determine the extent to which
other sources of noise are regulated, including commercial, industrial, and residential
activities. This report explains how noise is measured, identifies the sources of noise
that are currently regulated by the federal government, describes the extent to which the
federal standards limit noise, and explains the role of state and local governments. It
will be updated as developments warrant.
Introduction
According to the National Institute on Deafness and Other Communication
Disorders, exposure to loud sounds is responsible for hearing impairment in 10 million
of the nearly 30 million people with hearing loss in the United States. Another 30 million
people are daily exposed to dangerous noise levels. Many individuals are also regularly
exposed to sound levels that may not lead to hearing loss, but can be intrusive and impair
one’s quality of life. Several federal laws require the federal government to provide
uniform standards for various sources of noise. The responsibility for setting and
enforcing these standards is divided among multiple federal agencies. In the past, the
Environmental Protection Agency (EPA) coordinated all federal noise control activities
through its Office of Noise Abatement and Control. However, Congress phased out the
office’s funding in FY1983 as part of a shift in federal noise control policy to transfer the
primary responsibility of regulating noise to state and local governments. Although EPA
no longer plays a prominent role in regulating noise, its past standards and regulations
Congressional Research Service ˜ The Library of Congress

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remain in effect, and other federal agencies continue to set and enforce noise standards
for sources within their regulatory jurisdiction. Public interest in the adequacy of current
noise control standards continues to be strong, as sources of noise such as airports and
highways have expanded over time and as residential development has resulted in people
living closer to such sources.
How Loud Is Too Loud?
Sound is measured in units of decibels (dbA), and an increase of 10 dbA represents
sounds that are perceived to be twice as loud. Constant or repeated exposure to levels of
90 dbA or higher can lead to hearing loss.1 Although sounds quieter than 90 dbA are not
harmful to human hearing, most individuals perceive unwanted sounds in excess of 65
dbA to be intrusive. Exposure to such noise can impair one’s quality of life, depending
on the sensitivity of the individual and the frequency and duration of exposure.
Sound Levels Generated by Various Sources of Noise
Sound Level
dbA
Quiet library, soft whispers
30
Living room, refrigerator
40
Light traffic, normal conversation, quiet office
50
Air conditioner at 20 feet, sewing machine
60
Vacuum cleaner, hair dryer, noisy restaurant
70
Average city traffic, garbage disposals, alarm clock at 2 feet
80
Subway, motorcycle, truck traffic, lawn mower
90
Garbage truck, chain saw, pneumatic drill
100
Rock band concert in front of speakers, thunderclap
120
Gunshot blast, jet plane
140
Rocket launching pad
180
Source: Deafness Research Foundation.
What Sources of Noise Are Subject to Federal Regulation?
The Noise Control Act of 1972 (P.L. 92-574) and several other federal laws require
the federal government to set and enforce uniform noise standards for aircraft and
airports, interstate motor carriers and railroads, workplace activities, medium and heavy-
duty trucks, motorcycles and mopeds, portable air compressors, federal highway projects,
and federal housing projects. The Noise Control Act also requires federal agencies to
comply with all federal, state, and local noise requirements. Most federal noise standards
focus on preventing hearing loss by limiting exposure to sounds of 90 dbA and higher.
However, some are stricter and focus on limiting exposure to quieter levels that are
annoying to most individuals and can diminish one’s quality of life. In addition to
1 For more information on the effects of noise exposure on human hearing, see the National
Institutes of Health website at [http://www.nidcd.nih.gov].

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loudness, there has been some concern about the human health effects of low frequency
sound, which we can feel but not hear. At this time, noise control standards in the United
States do not regulate low frequency sound below the threshold of human hearing.
Current standards and the federal agencies that set and enforce them are discussed below.
Aircraft and Airports.2 The Aircraft Noise Abatement Act of 1968 (P.L. 90-411)
requires the Federal Aviation Administration (FAA) to develop and enforce safe standards
for aircraft noise.3 In developing these standards, the FAA generally follows the noise
restrictions established by the International Civil Aviation Organization (ICAO). Federal
noise regulations define aircraft according to four classes: Stage 1, Stage 2, Stage 3, and
Stage 4. Stage 1 aircraft are the loudest, and Stage 4 are the quietest. All Stage 1 aircraft
have been phased out of commercial operation, and all unmodified Stage 2 aircraft over
75,000 pounds were phased out by December 31, 1999, as required by the Airport Noise
and Capacity Act of 1990 (P.L. 101-508, Subtitle D).4 Stage 3 aircraft must meet separate
standards for runway takeoffs, landings, and sidelines, ranging from 89 to 106 dbA
depending on the aircraft’s weight and its number of engines.5 Stage 4 standards are
stricter and require a further reduction of 10 dbA overall relative to Stage 3 standards.
The Stage 4 standards are relatively new and are based on standards that the ICAO
adopted in June 2001 (referred to as “Chapter 4” in ICAO parlance). The FAA proposed
the Stage 4 standards in December 20036 and finalized them in July 2005,7 adopting the
ICAO standards by reference. The Stage 4 standards apply to newly manufactured
airplanes for which a new design is submitted for airworthiness certification on or after
January 1, 2006. As the majority of aircraft designed in recent years are already quiet
enough to attain the Stage 4 standards, some have commented that the impact of the
stricter standards on most aircraft manufacturers may be less significant than otherwise.
At this time, existing Stage 3 aircraft also will be allowed to continue operation.

In addition to aircraft certification standards, airports receiving federal funds are
required to meet noise control standards for their operation, based on land use. The
standards range from 65 dbA for residential areas to over 85 dbA for agricultural and
transportation uses.8 The Airport and Airway Improvement Act of 1982 (P.L. 97-248)
established the Airport Improvement Program (AIP) to provide federal assistance for
airport construction projects and to award grants for mitigating noise resulting from the
expansion of airport capacity. Airport operators applying for such grants must design
noise exposure maps and develop mitigation programs to ensure that noise levels are
compatible with relevant land uses, noted above.
2 For more information on aircraft noise, see the FAA’s website at [http://www.aee.faa.gov].
3 49 U.S.C. 44715
4 49 U.S.C. 47528
5 14 C.F.R. 36
6 68 Federal Register 67329-67336.
7 70 Federal Register 38742-38750.
8 14 C.F.R. 150

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Interstate Motor Carriers. The Noise Control Act required EPA to develop noise
standards for motor carriers engaged in interstate commerce, and it authorized the Federal
Highway Administration to enforce them.9 All commercial vehicles over 10,000 pounds
are subject to standards for highway travel and stationary operation, but the standards do
not apply to sounds from horns or sirens when operated as warning devices for safety
purposes.10 For highway travel, the standards range from 81 to 93 dbA, depending on the
speed of the vehicle and the distance from which the sound is measured. The standards
for stationary operation are similar and range from 83 to 91 dbA, depending on the
distance from the vehicle. The standards apply at any time or condition of highway grade,
vehicle load, acceleration, or deceleration.
Interstate Railroads. The Noise Control Act also required EPA to establish noise
standards for trains and railway stations engaged in interstate commerce, and it authorized
the Federal Railroad Administration to enforce them.11 The standards do not apply to
sounds from horns, whistles, or bells, when operated as warning devices for safety
purposes. There are separate standards for locomotives, railway cars, and railway station
activities such as car coupling.12 For locomotives built before 1980, noise is limited to
73 dbA in stationary operation and at idle speeds, and is limited to 96 dbA at cruising
speeds. The standards for locomotives built after 1979 are stricter, and limit noise in
stationary operation and at idle speeds to 70 dbA and at cruising speeds to 90 dbA. Noise
from railway cars must not exceed 88 dbA at speeds of 45 miles per hour (mph) or less,
and must not surpass 93 dbA at speeds greater than 45 mph. Noise from car coupling
activities at railway stations is limited to 92 dbA.
Workplace Activities. The Occupational Safety and Health Act of 1970 (P.L. 91-
596) required the Occupational Safety and Health Administration (OSHA) to develop and
enforce safety and health standards for workplace activities.13 To protect workers, OSHA
established standards which specify the duration of time that employees can safely be
exposed to specific sound levels.14 At a minimum, constant noise exposure must not
exceed 90 dbA over 8 hours. The highest sound level to which workers can constantly
be exposed is 115 dbA, and exposure to this level must not exceed 15 minutes within an
8-hour period. The standards limit instantaneous exposure, such as impact noise, to 140
dbA. If noise levels exceed these standards, employers are required to provide hearing
protection equipment that will reduce sound levels to acceptable limits.
Other Regulated Sources of Noise. The Noise Control Act directed EPA to
set and enforce noise standards for transportation, construction, and electrical equipment,
and motors or engines.15 Under this authority, EPA established standards for motorcycles
and mopeds, medium and heavy-duty trucks over 10,000 pounds, and portable air
9 42 U.S.C. 4917
10 49 C.F.R. 325
11 42 U.S.C. 4916
12 49 C.F.R. 210
13 29 U.S.C. 655
14 29 C.F.R. 1910.95
15 42 U.S.C. 4905

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compressors. The standards for motorcycles only apply to those manufactured after 1982
and range from 80 to 86 dbA, depending on the model year and whether the motorcycle
is designed for street or off-road use.16 Noise from mopeds is limited to 70 dbA. The
standards for trucks over 10,000 pounds only apply to those manufactured after 1978 and
range from 80 to 83 dbA depending on the model year.17 These standards are separate
from those for interstate motor carriers. Noise from portable air compressors is limited
to 76 dbA.18 The Noise Control Act also authorized EPA to require labels for products
which reduce noise.19 Under this authority, EPA established Noise Reduction Ratings for
hearing protection devices which require manufacturers to identify the level of sound
from which the device protects the user.20
There also are noise standards for federal highway projects and federal housing
projects. The Federal-Aid Highway Act of 1970 (P.L. 91-605) required the Federal
Highway Administration to develop standards for highway noise levels that are
compatible with different land uses.21 The law prohibits the approval of federal funding
for highway projects that do not incorporate measures to meet these standards, which
range from 52 to 75 dbA depending on land use.22 Under general authorities provided by
the Housing and Urban Development Act of 1968 (P.L. 90-448), there also are standards
for federal housing projects located in noise exposed areas.23 The standards limit interior
noise to a daily average of 65 dbA.24
What Is the State and Local Role in Controlling Noise?
As discussed above, the federal role in regulating noise is mostly limited to
transportation, workplace activities, and certain types of machinery. State and local
governments determine the extent to which other sources of noise are controlled, and
regulations for such sources can vary widely among localities. Further, some states do not
directly regulate noise, but allow local governments to play the primary role. Sources of
noise commonly regulated at the state and local level include commercial, industrial, and
residential activities. Regulations for such sources typically control the public’s exposure
to irritating or potentially harmful noise levels by limiting the activity concerned to
specific times of the day, such as the operation of domestic power tools or gasoline-
powered lawn equipment in residential areas.
16 40 C.F.R. 205, Subparts D and E
17 40 C.F.R. 205, Subpart B
18 40 C.F.R. 204
19 42 U.S.C. 4907
20 40 C.F.R. 211
21 23 U.S.C. 109(i)
22 23 C.F.R. 772
23 42 U.S.C. 3535(d)
24 24 C.F.R. 51, Subpart B.

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