The Aliso Canyon Natural Gas Leak: State and Federal
Response and Oversight
March 9, 2016 (IN10461)
Richard K. Lattanzio
Paul W. Parfomak
Richard K. Lattanzio, Specialist in Environmental Policy (email@example.com, 7-1754)
Paul W. Parfomak, Specialist in Energy and Infrastructure Policy (firstname.lastname@example.org, 7-0030)
Between October 23, 2015, and February 11, 2016, the Aliso Canyon Underground Storage Facility near the Porter
Ranch community in Los Angeles County, California, experienced a large and uncontrolled natural gas leak.
The Aliso Canyon facility, owned and operated by Southern California Gas Company (SoCalGas), a subsidiary of
Sempra Energy, is a depleted oil field that was converted to a natural gas storage reservoir in the 1970s. The facility
provides natural gas to the Los Angeles region for residential heating and cooking, for commercial and industrial uses,
and as a fuel for electric power plants. According to the Energy Information Administration, the Aliso Canyon facility
is the fourth largest among 418 underground natural gas storage sites in the United States.
The leak was reportedly caused by damage to a well casing approximately 500 feet underground. The incident released
an estimated 5.4 billion cubic feet of natural gas into the atmosphere—equivalent to 94,000 metric tons of methane, a
potent greenhouse gas. The risk to safety from the fugitive methane and the presence of odorants and other chemicals in
the gas led to the temporary relocation of over 2,000 households and two schools. For more on the incident's emissions
and their impacts, see CRS Insight IN10448, The Aliso Canyon Natural Gas Leak: Public Health and Environmental
State and Local Response and Oversight
SoCalGas is an investor-owned utility in the state of California, permitted and regulated by the California Public
Utilities Commission (CPUC). Principal oversight and accident response authorities rest with state and local agencies.
The California governor's office reported that state agency response included:
Coordination by the Governor's Office of Emergency Services;
Oversight of SoCalGas's relief activities by the Division of Oil, Gas, and Geothermal Resources (DOGGR) within
the California Department of Conservation (DOC); the CPUC; and the California Energy Commission;
Monitoring of public health and welfare and environmental impacts by the Division of Occupational Safety and
Health within the California Department of Industrial Relations and the Office of Environmental Health Hazard
Assessment and the California Air Resources Board (including the South Coast Air Quality Management
District) within the California Environmental Protection Agency.
DOGGR has launched an investigation to determine the root cause of the leak and whether any state statutory or
regulatory violations occurred. Further, the CPUC has initiated a staff investigation of SoCalGas's actions before and
after the incident.
As a result of the leak, the DOC has adopted emergency safety regulations for all underground natural gas storage
facilities in the state under California's emergency rulemaking process.
The federal government has provided technical assistance in response to the Aliso Canyon incident through a variety of
entities. These include the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Transportation's
Pipeline and Hazardous Materials Safety Administration (PHMSA).
Existing statutes and regulations that may authorize the federal government to address such incidents include:
The Natural Gas Pipeline Safety Act of 1968, codified as 49 U.S.C. 60101 et seq., authorizes PHMSA to
promulgate minimum safety standards for natural gas pipeline facilities (49 C.F.R Parts 100-185). However,
court decisions from two different federal circuits (7th and 10th) are split on whether underground storage
reservoirs are classified as "facilities." Currently, PHMSA defers to state agencies, such as the CPUC, to regulate
the safety of underground natural gas storage sites within their borders. Further, the agency has worked with
industry to develop voluntary safety standards for sites in depleted hydrocarbon reservoirs and salt canyon
reservoirs. After the Aliso Canyon incident, PHMSA issued a bulletin advising (but not requiring) all storage site
operators to follow these voluntary standards.
The Emergency Powers provisions of Section 303 of the Clean Air Act, codified at 42 U.S.C. 7603, authorizes
EPA to bring suit, issue orders, or take other action as necessary—in consultation with appropriate state and local
authorities—"upon receipt of evidence that a pollution source ... is presenting an imminent and substantial
endangerment to public health or welfare, or the environment." Additional enforcement authorities to respond to
an actual or threatened accidental release of a regulated substance from a stationary source are provided under
Section 112(r)(9) of the Clean Air Act, codified at 42 U.S.C. 7412. Herein, methane is designated as a regulated
flammable substance. (Federal law generally exempts natural gas from classification as either a solid or
hazardous waste under the Resource Conservation and Recovery Act of 1976 (P.L. 94-580), as amended, or from
federal response and liability authorities under the Comprehensive Environmental Response, Compensation, and
Liability Act of 1980 (P.L. 96-510), as amended.)
New Federal Standards
Several bills to reauthorize PHMSA in the 114th Congress would require the agency to promulgate minimum federal
safety standards for underground natural gas storage facilities. The Securing America's Future Energy: Protecting
Infrastructure of Pipelines and Enhancing Safety (SAFE PIPES) Act (S. 2276) and the Natural Gas Leak Prevention
Act (H.R. 4429) would require PHMSA to issue regulations within two years. The Underground Storage Safety Act
(H.R. 4578) would require the agency to issue regulations within 180 days, requiring, at a minimum, operator
compliance with the current voluntary safety standards referenced in PHMSA's advisory bulletin. Whether or not these
bills are enacted, President Obama has reportedly committed to direct PHMSA to promulgate safety standards under
the agency's existing statutory authority.
EPA Administrator Gina McCarthy has reportedly stated an intent for the agency to "do more" to curb methane
emissions from existing sources in the oil and gas industry. Currently, the Administration is scheduled to finalize new
source performance standards for the sector this summer. As proposed, the rules would not cover the Aliso Canyon
facility, because, among other reasons, (1) the standards apply to new and modified sources of emissions, not existing
ones, and (2) the standards do not list underground storage facilities as a covered source category.