The EPA has issued 2 (long awaited) draft final vapor intrusion documents for public comment. These guidance documents are intended to help ensure vapor intrusion assessment and mitigation actions to protect human health are undertaken in a technically, scientifically and nationally consistent manner.
The guidance documents describe EPA’s current recommendations for how to identify and consider key factors when assessing vapor intrusion, making risk management decisions, and implementing mitigation pertaining to this potential human exposure pathway. They’re intended for both residential and non-residential buildings that may be impacted by vapor intrusion from subsurface contamination.
The first document is entitled: Final Guidance for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Sources to Indoor Air.
The broad concepts of this guidance document are generally applicable to petroleum hydrocarbons. However, it’s intended more to apply to compounds other than petroleum (like chlorinated solvents), other compounds when they’re mixed with petroleum, and petroleum from refineries and terminals. It’s not intended to apply to petroleum releases from underground storage tanks (USTs). Which is why the EPA also issued….
Petroleum From USTs
The second draft document is entitled: Guidance for Addressing Petroleum Vapor Intrusion at Leaking Underground Storage Tank Sites.
This guidance focuses on USTs, typically located at gas stations and non-marketing facilities regulated under Subtitle I of the Solid Waste Disposal Act. This guidance describes how to address risks solely from petroleum hydrocarbon vapors as a result of USTs.
Combined these two documents give us 294 pages of vapor intrusion guidance. Enjoy! The EPA is seeking public input on the vapor intrusion guidance through May 24, 2013.