EPA Uses Superfund and TSCA to Address Indoor Air Contamination
Following the lead of many state environmental protection agencies (including MassDEP), on December 7, the EPA issued a final rule to add “vapor intrusion” as a fifth criterion under the Hazard Ranking System (HRS) to determine whether to add a contaminated site to the Superfund program. The rule will be effective 30 days after its publication in the Federal Register.
In addition to screening sites based on contaminated soil and groundwater, EPA will now account for the site’s potential for “subsurface intrusion” (SsI), the most common form of which is vapor intrusion — that is, the migration of hazardous substances from subsurface soil or groundwater into buildings through cracks in basements, foundations, sewer lines and other openings.
For years, EPA has addressed potential vapor intrusion in the remediation of Superfund sites. Now, a site can be listed as a Superfund site because of vapor intrusion. This may make more sites eligible for the National Priorities List (NPL), a list of the sites most in need of federal attention. EPA may also re-evaluate sites it previously declined to list.
The Future of Vapor Intrusion Regulation: Federal and State
It remains to be seen how aggressively, or even whether, EPA will pursue the Superfund program and new NPL listings based on vapor intrusion under the new Trump administration.
Regardless of EPA’s stance, enforcement of vapor intrusion regulations will continue in many states based on evolving theories of vapor intrusion risk assessment. For example, in April 2016, MassDEP announced that it would revisit nearly 1000 sites that it administratively closed under prior environmental remediation standards. And in October, MassDEP published a Vapor Intrusion Guidance outlining its approach to addressing sites with vapor intrusion problems.
EPA Proposes TCE Ban
Also this month, EPA proposed to invoke its authority under the Toxic Substances Control Act to ban two substances with a possibility to migrate underground, TCE and PCE, as degreasers and spot-removing agents in dry cleaning. This is the first time since the late 1980s that EPA has attempted to restrict a hazardous chemical under TSCA. Its last attempt to do so was for asbestos in 1989, but that was overturned in court.
Recent revisions to TSCA, known as the Frank R. Lautenberg Chemical Safety for the 21st Century Act, may give EPA an easier path to ban the chemicals as EPA no longer needs to demonstrate that banning a chemical is the “least burdensome” way to reduce risk. It can instead restrict a chemical “to the extent necessary” to reduce the risk. Again, it remains to be seen how this will play out under the new administration.
Image Credit: EPA – Simplified sketch of “subsurface intrusion.”