A draft proposed rule that could exempt the geologic sequestration of carbon dioxide (CO2) from federal hazardous waste regulations is now moving through the regulatory process. On March 22, 2011, the U.S. Environmental Protection Agency (USEPA) sent a draft proposed rule to the White House Office of Management & Budget (OMB) that could conditionally exempt CO2 sequestered underground from Resource Conservation and Recovery Act (RCRA) requirements. It appears the rule would address the RCRA liability of owners and operators of carbon capture and sequestration (CCS) wells should CO2 leak and contaminate underground sources of drinking water. Following regulatory review by OMB, USEPA anticipates that the proposed rule will be published in the Federal Register in May 2011.

You’ll recall that on December 10, 2010, USEPA finalized a rule under the Safe Drinking Water Act’s Underground Injection Control Program (SDWA UIC Program) to create a new class of injection wells (Class VI) for geological sequestration of CO2. The new rule does not currently address the long-standing concern that owners and operators of Class VI wells could be liable under RCRA for environmental contamination should CO2 that meets the definition of a hazardous waste leak from the wells and contaminate underground sources of drinking water. The draft proposed rule before OMB explores a number of options, including a conditional exemption from the RCRA requirements for hazardous CO2 streams in order to facilitate implementation of geologic sequestration while protecting human health and the environment.

A CO2 Stream with Impurities Could Trigger RCRA Requirements

Under USEPA’s regulations, a solid waste is a hazardous waste if, among other things, it exhibits the characteristics of toxicity. While a CO2 stream is not itself a listed hazardous waste, captured CO2 could contain some impurities at levels that would require its classification as a “characteristic” hazardous waste. CO2 captured from sectors amenable to CCS, such as electric generating facilities, could contain toxic chemical constituents including arsenic, mercury, and selenium. A captured CO2 stream that meets the definition of a hazardous waste would have to comply with all applicable RCRA requirements.

As a result, the characterization of a CO2 stream as “hazardous waste” would make the RCRA waste management scheme applicable to the generation, transportation, treatment, sequestration, and/or disposal of the CO2 stream. Presumably, this could mean that underground injection and sequestration of a hazardous CO2 stream would need to meet the requirements for Class I hazardous waste wells under the SDWA UIC Program instead of the Class VI geologic sequestration wells.

But Not if the CO2 Stream is Exempt from RCRA

The draft proposed rule is not publically available, but an exemption from RCRA might allow the injection of a “characteristically” hazardous CO2 stream for the purpose of geologic sequestration to be permitted under the Class VI injection well requirements instead of Class I requirements. Interestingly, an exemption from RCRA could close a potential (and overlooked) gap that would enable owners and operators of CO2 sequestration wells to seek Class I well permits in order circumvent the stringent post-closure monitoring, care, and financial responsibility requirements imposed by the Class VI rules. On the other hand, owners and operators of CO2 sequestration wells would be able to avoid the complexities and inefficiencies of the RCRA regulatory regime. Most importantly, the exemption would provide much desired regulatory certainty to the CCS industry. Stay tuned.