The Impact of RCRA Land Disposal Restrictions on Class I Hazardous Waste Injection
The Hazardous and Solid Waste Amendments (HSWA) to the Resource Conservation and Recovery Act (RCRA) prohibit land disposal of restricted hazardous waste. The prohibition includes injection of hazardous waste into Class I wells.
The HSWA Amendments include a provision that allows an operator to petition the EPA Administrator for an exemption to the land disposal prohibition. The exemption requires the operator to demonstrate that there will be no migration of hazardous constituents from the injection zone for as long as the wastes remain hazardous. The length of time required for the demonstration has been defined in the regulations as 10,000 years. The formal demonstration has become known as a Class I no migration petition. The approval process for the no migration petiton requires a signature by a regional EPA Administrator, or his or her designee.
The UIC regulations outline the standards and procedures for seeking an exemption from the land disposal prohibition. The regulations also establish the requirements for preparing and submitting a no migration petition demonstration. Requirements include the technical information that supports the petition, information regarding the review, public participation, approval or denial of a petition, and the opportunity to modify or reissue a petition.
Only four EPA Regions have approved Class I no migration petitions. In general this is due to:
- The occurrence of industries that generate large volumes of wastewater
- The presence of the geologic conditions suitable for disposal of large volumes of wastewater
Suitable geologic conditions require a disposal formation that is:
- Below the lowest underground source of drinking water
- Sufficient in thickness, areal extent, and interconnected pore space to accept the large volumes of wastewater
- Overlain by confining layers of impermeable rocks such as shales, nonporous carbonates, salt or anhydrite to prevent upward movement of the injected waste
This confining layer isolates the waste within the disposal formations for as long as the waste remains hazardous. The Gulf Coast region of the U.S. contains this type of geology. More than 60% of all active no migration petitions are found in the Gulf Coast region because of this mix of industry and suitable geology.
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Since EPA Region 6 has most active no migration petition program the region has established guidelines to assist operators in preparing no migration demonstrations.