In the 1990’s, some states begin requiring evaluation of the Vapor Intrusion Pathway.
The American Society for Testing and Materials (ASTM) develops Risk-Based Corrective Action (RBCA) standard for petroleum releases including vapor intrusion.
It wasn’t until investigative work of the Massachusetts Department of Environmental Protection (MassDEP) in the 1990’s that regulators began to understand the significance of vapor intrusion By mid – 1990’s, some states (MA, MI, CT, and RI) required the vapor intrusion exposure pathway be evaluated during environmental site assessments.
The Redfield site in Colorado was one of the first major sites to bring the vapor intrusion issue to the attention of the U.S. Environmental Protection Agency (USEPA) and the nation in the late 1990’s.
- Relatively low concentrations of 1,1-dichloroethene (1,1-DCE) in groundwater were found to have impacted indoor air in a large number of homes overlaying the solvent plume.
Vapor intrusion was not a regulatory concern when the HRS was revised in 1990, the vapor intrusion pathway was (is) not one of the pathways that are evaluated when scoring a site.