EPA's June 2015 final
vapor intrusion guide (OSWER publication 9200.2-154) presents current technical recommendations of the EPA for assessing and responding to vapor intrusion. The guide clarifies topics such as weighing multiple lines of evidence; statutory authorities for preemptive mitigation or other early actions; options for mitigation systems (including their operation, maintenance and monitoring); termination of response actions; and the role of institutional controls in final cleanup plans when subsurface vapor sources are present. The guide is intended for use at any site (and any building or structure on a site) being evaluated by EPA pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) or the corrective action provisions of the Resource Conservation and Recovery Act (RCRA), EPA's brownfield grantees, or state agencies acting pursuant to CERCLA or an authorized RCRA corrective action program where vapor intrusion may be of potential concern. The guide pertains to all of the various vapor-forming chemicals that may occur as subsurface contaminants at these sites, which include many non-chlorinated compounds (petroleum hydrocarbons, for example) and compounds that are not used as solvents. One of the main purposes of this guide is to promote national consistency in assessing the vapor intrusion pathway at these sites.
EPA's June 2015
petroleum vapor intrusion guide (EPA 510-R-15-001) focuses on releases of petroleum-based fuels, including petroleum hydrocarbon (PHC) and non-PHC fuel additives, from underground storage tanks (USTs) regulated under Subtitle I of the Solid Waste Disposal Act of 1984, which are typically located at gas stations. The guide may also be helpful when addressing petroleum contamination at comparable non-UST sites. Supporting technical information in the guide addresses topics such as light non-aqueous phase liquid, seasonal and weather effects and vapor intrusion attenuation factors.
The Vapor Intrusion Screening Level (VISL) Calculator is a technical resource developed by EPA that: (1) identifies chemicals considered to be typically vapor-forming and known to pose a potential cancer risk or noncancer hazard through the inhalation pathway; (2) provides generally recommended screening-level concentrations for groundwater, near-source soil gas (exterior to buildings), sub-slab soil gas, and indoor air based on default exposure scenarios and default risk management benchmarks; and (3) facilitates calculation of site-specific screening levels and candidate cleanup levels based on user-defined target risk levels, exposure scenarios, and semi-site-specific or site-specific attenuation factors. The VISL Calculator is an MS Excel workbook that was first published online in 2012. It has been updated periodically as new toxicity information became available and was recently updated to coincide with release of the OSWER Technical Guide. To download the spreadsheet calculator, visit EPA's online compendium of
technical information.
EPA's
Vapor Intrusion website is a resource for key information on vapor intrusion for both the general public and environmental professionals. The website contains basic information about vapor intrusion, technical and policy documents, tools and other resources to support vapor intrusion investigations. It also provides access to technical reports focused on topics such as conceptual model scenarios for the vapor intrusion pathway and mitigation approaches for vapor intrusion.
The National Institute of Environmental Health Sciences (NIEHS) Superfund Research Program funds university-based multidisciplinary research on human health and environmental issues related to hazardous substances. The central goal of the program is to understand and break the link between chemical exposure and disease.
Measuring Vapor Intrusion to Estimate Underground Contamination (Research Brief 238) describes process models developed by Brown University researchers to predict the concentrations of vapors that enter indoor environments.
Developments toward Low-Cost, Unattended Vapor Intrusion Monitoring(Research Brief 236) describes an inexpensive vapor intrusion monitoring system developed by NIEHS Superfund Research Program-funded scientists from the chemical sensor company Seacoast Science.
Two projects on distinguishing vapor intrusion from indoor sources of volatile organic compounds (VOCs) merited the Environmental Security Technology Certification Program (ESTCP) 2014 Project-of-The-Year Award for Environmental Restoration.
Use of Compound-Specific Stable Isotope Analysis to Distinguish Between Vapor Intrusion and Indoor Sources of VOCs (ER-201025) demonstrated use of a step-by-step protocol that can provide an independent line of evidence to determine whether or not buildings are impacted by VOCs. Use of On-Site GC/MS Analysis to Distinguish between Vapor Intrusion and Indoor Sources of VOCs(ER-201119) validated a step-wise investigation procedure using portable, commercially available gas chromatograph/mass spectrometer analysis and real-time decision making to distinguish between vapor intrusion and indoor sources of VOCs.