The U.S. Environmental Protection Agency (EPA) will be expanding their review of vapor intrusion at sites being evaluated under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), Resource Conservation and Recovery Act (RCRA), Brownfields, or states with authority to implement CERCLA or RCRA. Vapor intrusion is the migration of hazardous vapors from subsurface contamination such as soil or groundwater into indoor air. On April 16, EPA released for public input, two draft final vapor intrusion guidance documents, one general guidance applying to all compounds and one focused guidance applying to petroleum hydrocarbons released from underground storage tanks. The comment deadline is June 24, 2013. In a related development, due to be finalized in 2013, ASTM International will revise standards regarding due diligence, ASTM E1527-05 for Phase I Environmental Site Assessments (ESA), to include vapor intrusion.
What EPA programs will be affected?
The EPA currently reviews the effectiveness of remedies at CERCLA sites during five-year reviews. The EPA will be required to consider vapor intrusion as part of the evaluation of remedy effectiveness during five-year superfund reviews, and will expand evaluations of migrating vapor intrusion in nonresidential buildings such as schools, hotels, and hospitals. The addition of a review of vapor intrusion will apply to sites even if vapor intrusion was not included in the original remedial assessment.
The EPA also plans to consider vapor intrusion for sites in other programs, such as brownfields and others undergoing remediation under EPA oversight. This EPA guidance may be used by state implemented remediation programs.
The revised Phase I ESA standard (ASTM E1527-13, as it will be known), if adopted, will also include a review of the vapor pathway. The new ASTM E1527-13 will need to be approved by EPA as meeting the All Appropriate Inquiry (AAI) requirement.
How will it change the way vapor intrusion is evaluated?
Included in the changes for remediation sites, the final EPA guidance will contain new toxicity values for constituents that will alter the acceptable indoor air screening levels and change the process for remediating properties affected by volatile and semi-volatile organic compounds. The guidance will use a “multiple lines of evidence” approach to evaluate vapor intrusion risks that are likely to result in increased sampling of off-site properties.
In the revised ASTM Phase I ESA standard, evaluation of vapor intrusion pathways will be required in an assessment of recognized environmental conditions (RECs) or other environmental concerns. This will be achieved by an expanded regulatory file review of vapor intrusion and evaluation of off-site sources of vapor intrusion.
Where can my company obtain more information?
The EPA’s draft vapor intrusion guidance and information about the existing vapor intrusion program is available at http://www.epa.gov/oswer/vaporintrusion/.