On June 26, 2008 EPA released an external review draft of the Toxicological Review of Tetrachloroethylene. A public comment period of 90 days is provided. The document proposed an inhalation reference concentration (RfC) of 0.02 mg/m3 and an oral reference dose (RfD) of 0.004 mg/kg-day. The cancer assessment found that PCE is likely to be carcinogenic to humans by all routes of exposure. The review recommends an inhalation unit risk value range of 2 x 10-6 to 2 x 10-5 per ug/m3 and an oral slope factor range of 1 x 10-2 to 1 x 10-1 per mg/kg-day. The lengthy document may be found at:

In February 2008 the ASTM International Committee on Soil and Rock began work on a new standard, WK Practice for Active Soil Gas Sampling in the Vadose Zone for Vapor Intrusion Evaluations. It is anticipated that the new standard will present three sampling techniques: sampling at discrete depths, sampling over a small screened interval, and sampling using permanent vapor monitoring wells. An announcement of the initiation of work on the standard can be found at:

In March EPA issued the document: "Brownfields Technology Primer: Vapor Intrusion Considerations for Redevelopment". The document includes information on assessing the potential for vapor intrusion as well as mitigation options. Appendix A is a listing of State vapor intrusion guidance documents. The document may be found at:

In May 2008 the San Francisco Bay Regional Water Quality Board revised its document "Screening for Environmental Concerns at Sites with Contaminated Soil and Groundwater". Tables E through E-4 contain screening levels for groundwater, shallow soil gas, and indoor air for soil vapor concerns. Shallow soil gas screening levels are provided using both the attenuation factors developed by the California Department of Toxic Substances Control and those developed for use in the San Francisco Bay Region. Screening levels for soil are not provided because of concerns regarding contaminant loss during sampling. The revised document can be found at:

The EPA urban air toxics monitoring program reports are available at the following web site:

The Interstate Technology and Regulatory Council (ITRC) vapor intrusion team, in conjunction with the Oregon Department of Environmental Quality, is offering a 2 day classroom vapor intrusion course on October 7 and 8, 2008 in Portland, OR. The workshop will cover both assessment and mitigation. The instructors are John Boyer of NJDEP, Bill Morris of KDHE, Blayne Hartman, co-founder of H&P Mobile Geochemistry, Todd McAlary of Geosyntec, and Dave Folkes of EnviroGroup. Registration information is found at:

ITRC will be offering its web based training course "Vapor Intrusion Pathway: A Practical Guideline" on July 29, 2008 from 2:00 PM-4:15 PM EST. Dave Folkes of EnviroGroup is one of the instructors, covering the mitigation section of the ITRC guidance. Registration information is available at: