The United States Interstate Technology Regulatory Council (ITRC) has a compiled a team to review the 2007 version of its Vapor Intrusion Guidance document. This Team will review and update information contained in the previous ITRC documents, and create a new comprehensive web-based guidance document and training products.

Vapor intrusion is the migration of volatile chemicals from the subsurface into overlying buildings. Volatile chemicals may include volatile organic compounds, select semivolatile organic compounds, and some inorganic analytes, such as elemental mercury and hydrogen sulfide. Vapor intrusion requires three components: a source, an inhabited building, and a pathway from the source to the inhabitants. Vapor intrusion has become a significant environmental issue for regulators, industry leaders, and concerned residents.

Volatile organic contaminants in subsurface soil and groundwater are a recognized problem. Often, this contamination exists beneath occupied lands. Indoor air contaminant levels may be significant enough at sites with subsurface contamination to cause immediate regulatory action in some cases and drive remediation in others.

The 2007 version of the guide was developed the Interstate Technology & Regulatory Council (ITRC) Vapor Intrusion Team and represents the combined effort of more than 100 professionals from state and federal regulatory agencies, consultants, industry, and stakeholders. It is a practical, easy-to-read, how-to guideline for assessing the vapor intrusion pathway.

The 2007 Guideline, consists of four chapters: (1) An overview of vapor intrusion; (2) Preliminary screening of sites; (3) Site investigation; and (4) Mitigation.