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EPA Releases Long-Awaited Vapor Intrusion Technical Guidance Documents

On June 11, 2015, EPA released two technical guidance documents for evaluating vapor intrusion:

  • OSWER Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air (VI Guidance)
  • Technical Guide for Addressing Petroleum Vapor Intrusion at Leaking Underground Storage Tank Sites (Petroleum UST VI Guidance)

The VI Guidance provides a five-step process for evaluating whether the VI exposure pathway is complete and recommendations for completing a human health risk assessment, as well as mitigation measures, if necessary. The Petroleum UST VI Guidance considers the degradation of petroleum in the vadose zone and relies on separation distances to establish whether VI is a potentially complete exposure pathway.

ToxStrategies scientists and engineers have substantial experience addressing the vapor intrusion pathway. Example projects include modeling potential migration of vapors from the subsurface into building interiors, developing indoor air sampling plans, conducting indoor air sampling, developing applicable health-based screening levels, and assisting clients with community outreach.

Both documents can be found here.