The U.S. Environmental Protection Agency (EPA) has just announced a proposed rule to add a subsurface intrusion (SsI) component to the Superfund Hazard Ranking System (HRS). Addition of a Subsurface Intrusion Component to the Hazard Ranking System, RIN 2050-AG67 (February 3, 2016).
By adding the consideration of vapor intrusion, hundreds of sites that previously would not rank high enough to qualify for listing on the National Priorities List (NPL) would now likely qualify. NPL listing is a prerequisite to EPA spending sums over $2 million to conduct remedial actions. NPL-listed sites are generally more expensive to remediate and more difficult to sell than are other environmentally distressed properties.
In its support materials, the EPA noted that the Government Accountability Office (GAO) had concluded that “if vapor intrusion sites are not assessed and, if needed, listed on the NPL, there is the potential that contaminated sites with unacceptable human exposure will not be acted upon.” The HRS is Appendix A to the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), and is used by EPA to identify hazardous waste sites eligible to be added to the NPL.
SsI can be defined as the migration of hazardous substances, pollutants, or contaminants from contaminated groundwater or soil into an overlying building. SsI may result in exposure to harmful levels of hazardous substances, that may be amplified by extended time spent in buildings where SsI occurs. The EPA claims that this may raise the lifetime risk of cancer or chronic disease. In an effort to ensure that SsI contamination is consistently evaluated, the EPA has proposed to add an HRS component that will allow EPA to evaluate threats posed by SsI.
The Agency has provided an HRS Subsurface Intrusion webpage to afford the regulated community and interested parties with more detailed information on the rulemaking.
The EPA Administrator, Gina McCarthy, signed the Notice of Proposed Rulemaking on February 3, 2016. The public comment period for the proposed rule will be sixty days from the date of publication in the Federal Register.