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Underground Injection Control Program |  |
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What is the UIC program?Summary of the history
of the UIC program What is Underground Injection? Underground injection is the technology of placing fluids underground, in porous formations of rocks, through wells or other similar conveyance systems. While rocks such as sandstone, shale, limestone appear to be solid, they can contain significant voids or pores that allow water and other fluids to fill and move through them. Man-made or produced fluids (liquids, gases or slurries) can move into the pores of rocks by the use of pumps or by gravity. The fluids may be water, wastewater or water mixed with chemicals. Injection well technology can predict the capacity of rocks to contain fluids and the technical details to do so safely. Why Do We Need a Program to Regulate the Placement of Fluids Underground? Facilities across the United States and in Indian Country discharge a variety of hazardous and nonhazardous fluids into more than 400,000 injection wells. While treatment technologies exist, it would be very costly to treat and release to surface waters the billions and trillions of gallons of wastes that industries produce each year. Agribusiness and the chemical and petroleum industries all make use of underground injection for waste disposal. When wells are properly sited, constructed, and operated, underground injection is an effective and environmentally safe method to dispose of wastes. The Safe Drinking Water Act established the Underground Injection Control (UIC) Program to provide these safeguards so that injection wells do not endanger current and future underground sources of drinking water (USDW). The most accessible fresh water is stored in shallow geological formations called aquifers and is the most vulnerable to contamination. These aquifers feed our lakes; provide recharge to our streams and rivers, particularly during dry periods; and serve as resources for 92 percent of public water systems in the United States. What Is an Injection Well? The UIC Program defines an injection well as any bored, drilled or a
driven shaft or a dug hole, where the depth is greater than the largest
surface dimension that is used to discharge fluids underground. This definition
covers a wide variety of injection practices that range from more than
100,000 technically sophisticated and highly monitored wells which pump
fluids into isolated formations up to two miles below the Earth's surface,
to the far more numerous on-site drainage systems, such as septic systems,
cesspools, and storm water wells, that discharge fluids a few feet underground. How Does the UIC Program Regulate the Very Different Types of Underground Injection? The EPA groups underground injection into five classes for regulatory control purposes. Each class includes wells with similar functions, and construction and operating features so that technical requirements can be applied consistently to the class. Class I includes the emplacement of hazardous and nonhazardous fluids (industrial and municipal wastes) into isolated formations beneath the lowermost USDW. Because they may inject hazardous waste, Class I wells are the most strictly regulated and are further regulated under the Resource, Conservation and Recovery Act. Class II includes injection of brines and other fluids associated with oil and gas production; Class III encompasses injection of fluids associated with solution mining of minerals; Class IV addresses injection of hazardous or radioactive wastes into or above a USDW and is banned unless authorized under other Statutes for ground water remediation. Class V includes all underground injection not included in Classes I-IV. Class V wells inject nonhazardous fluids into or above a USDW and are typically shallow, on-site disposal systems, such as floor and sink drains which discharge directly or indirectly to ground water, dry wells, leach fields, and similar types of drainage wells. Injection practices or wells which are not covered by the UIC Program include other individual residential waste disposal systems that inject ONLY sanitary waste and commercial waste disposal systems that serve fewer than 20 persons that inject ONLY sanitary waste. Are All Injection Wells Waste Disposal Wells? All injection wells are not waste disposal wells. Some Class V wells, for example, inject surface water to replenish depleted aquifers or to prevent salt water intrusion. Some Class II wells inject fluids for enhanced recovery of oil and natural gas, and others inject liquid hydrocarbons that constitute our Nation's strategic fuel reserves in times of crisis. How Does the UIC Program Prevent Contamination of Our Water Supply? Injection wells have the potential to inject contaminants that may cause our underground sources of drinking water to become contaminated. The UIC Program prevents this contamination by setting minimum requirements. The goals of the EPA's UIC Program are to prevent contamination by keeping injected fluids within the well and the intended injection zone, or in the case of injection of fluids directly or indirectly into a USDW, to require that injected fluids not cause a public water system to violate drinking water standards or otherwise adversely affect public health. These minimum requirements affect the siting of an injection well, and the construction, operation, maintenance, monitoring, testing, and finally, the closure of the well. All injection wells require authorization under general rules or specific permits. Finally, States may apply to have primary enforcement responsibility (primacy) for the UIC Program. To date, 33 States, Guam, the Commonwealth of the Mariana Islands, and Puerto Rico have obtained primacy for all classes of injection wells. Seven States share primacy with the EPA. The EPA administers UIC programs for the remaining States, the Virgin Islands, American Samoa and Indian Country. For More Information about the EPA's UIC Program Contact: The Safe Drinking Water Hotline (800) 426-4791 or the Office of Ground Water and Drinking Water (202) 260-7077. Write to: The UIC Program, Mail Code 4606, U.S. EPA, 401 M Street S.W., Washington, D.C. 20460. Please visit the web site at www.epa.gov/safewater.
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