United States Region 8 October 2008
Environmental Protection EPA 9Q8-R-08-002
Agency
EPA Approves the Assiniboine and Sioux
(Fort Peck) Tribes' Class II Underground
Injection Control Program in Montana
What is EPA's decision?
The U.S. Environmental Protection Agency (EPA) is announcing the approval of the Fort Peck
Tribes' Underground Injection Control (UIC) program. As a result of this action, the Fort Peck
Assiniboine and Sioux (Fort Peck) Tribes of Montana are authorized to administer and enforce
their own Class II (oil and gas-related) injection well program under the Safe Drinking Water
Act (SDWA). EPA's decision is based on careful and extensive legal and technical review of the
Tribes' primary enforcement or "primacy" application, all public comments received, and other
relevant information.
How did the Fort Peck Tribes obtain EPA's approval?
Indian tribes may apply for primacy for the UIC program if they meet specific eligibility
criteria and administrative and programmatic conditions. EPA has determined that the
Fort Peck Tribes are eligible to apply for primacy, that the Tribes' Class II UIC program
meets all applicable requirements for approval under SDWA Section 1425, and that the
Tribes are capable of administering an effective Class II UIC program in a manner
consistent with the SDWA and all applicable regulations. The Tribes' qualified UIC program
staff has been conducting compliance inspections of Class II injection wells under a Direct
Implementation Tribal Cooperative Agreement with EPA.
What activities will the Tribes regulate to protect groundwater?
Effective November 26, 2008, the Assiniboine and Sioux Tribes will regulate all existing and
future Class II injection wells located within the exterior boundaries of the Fort Peck Indian
Reservation. EPA has determined that the Tribes' UIC program fulfills federal regulatory
requirements to allow the safe disposal of these fluid wastes into the subsurface in a manner that
does not endanger current or future underground drinking water sources. The 24 Class II
injection wells currently operating on the Reservation are used to safely dispose of fluid wastes
(e.g., brines) brought to the surface during oil production. Almost all of these wells are owned
and operated by Tribal non-members.
The Tribes' Class II UIC regulations are specifically designed to protect underground sources of
drinking water. When oil and gas are extracted, large amounts of brine are typically brought to
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the surface. Often saltier than seawater, these fluid wastes typically contain high levels of salts
(total dissolved solids) and also may contain toxic metals and potentially hazardous petroleum
hydrocarbons such as benzene and toluene. By injecting the brine deep underground, Class II
wells prevent surface contamination of soil and water.
Under the UIC program, the Tribes will permit, monitor, and enforce regulations to ensure
injection wells are designed and maintained properly and that fluid disposal occurs in confined
subsurface locations with no connection to existing and potential drinking water sources.
In addition to the safe subsurface disposal of fluid wastes associated with oil and gas production,
Class II wells may also be used to inject fluids to enhance oil and gas recovery or for the storage
of hydrocarbons. The Tribes' UIC regulations cover all of these activities by requiring that oil
and gas lease owners and operators maintain the mechanical integrity of their injection wells and
adequately confine injected fluids in the subsurface. In general, EPA considers Class II injection
to be an environmentally preferable alternative to discharging oil and gas-produced waste fluids
to surface waters or pits.
How can I get more information?
The Federal Register publication date of the final rule, "Fort Peck Assiniboine and Sioux Tribes
in Montana; Underground Injection Control (UIC) Program; Primacy Approval and Minor
Revisions" is October 27, 2008. The rule and other supporting information can be accessed via
the web at www.regulations.gov. The public can also visit the EPA Region 8 UIC program's
web site at: http://www.epa.gov/region8/water/uic or contact Douglas Minter by email at
minter.douglas@epa.gov or by phone at 303-312-6079.
For more on EPA's UIC program and Class II wells, visit:
http://www.epa.gov/safewater/uic/wells class2.html
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