Lochgelly Underground Injection Control Site

Underground Injection Wells

What is an injection well? Widespread use of injection wells began in the 1930s to dispose of brine generated during oil production. Injection effectively disposed of unwanted brine, preserved surface waters, and in some formations, enhanced the recovery of oil. In the 1950s, chemical companies began injecting industrial wastes into deep wells. As chemical manufacturing increased, so did the use of deep injection. Injection was an inexpensive option for the disposal of unwanted and often hazardous industrial byproducts. EPA’s regulations group injection wells into six groups or “classes.” Classes I – IV and VI include wells with similar functions, construction, and operating features. This allows consistent technical requirements to be applied to each well class.  Class V wells are those that do not meet the description of any other well class.

In 1974, Congress passed the Safe Drinking Water Act (SDWA). Part of SDWA required EPA to report back to Congress on waste disposal practices, and develop minimum federal requirements for injection practices that protect public health by preventing injection wells from contaminating underground sources of drinking water (USDWs).  An underground source of drinking water (USDW) is an aquifer or a part of an aquifer that is currently used as a drinking water source or may be needed as a drinking water source in the future.

The UIC Program protects USDWs from endangerment by setting minimum requirements for injection wells. All injection must be authorized under either general rules or specific permits. Injection well owners and operators may not site, construct, operate, maintain, convert, plug, abandon, or conduct any other injection activity that endangers USDWs. The purpose of the UIC requirements is to:

  • Ensure that injected fluids stay within the well and the intended injection zone, or
  • Mandate that fluids that are directly or indirectly injected into a USDW do not cause a public water system to violate drinking water standards or otherwise adversely affect public health.

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