EPA Superfund Site

RAYTHEON CORP.

CA | EPA ID CAD009205097

About this site’s exposure pathways: As of September 2023, the Raytheon Corp. Superfund Site is considered “Insufficient Data to make a Human Exposure evaluation” (HEID) because of a newly identified exposure pathway and/or contaminant(s) that EPA found in shallow groundwater. Trichloroethene (TCE) and other Site volatile organic compounds (VOCs) may be infiltrating into the sanitary sewer lines and TCE vapors may be migrating along sewer laterals and entering sewer clean-outs and into buildings and bypassing the vapor intrusion remedy in place.

EPA uses this Human Exposure status when there is a lack of evidence to suggest that actual or reasonably anticipated human exposures are occurring and that those exposures are above acceptable risk-based levels. EPA's main concern is whether TCE from Site measured in indoor air pose an unacceptable risk of short-term and chronic health effects due to TCE inhalation exposure. The planned activities to collect sufficient information to evaluate this new exposure pathway and/or contaminants(s) are as follows: EPA has been implementing the 2010 vapor intrusion remedy to address buildings where elevated TCE and PCE concentrations have been found in indoor air. All nonresidential buildings overlying the shallow TCE groundwater contamination have been sampled to determine the appropriate response action and vapor intrusion control systems have been installed in all new buildings in the vapor intrusion study area. A Site-wide Shallow Zone Feasibility Study is currently underway to establish a framework and evaluate alternative groundwater cleanup technologies to address the source of vapor intrusion. The activities planned to make the Human Exposure Control determination include completion of the sewer pathway and building specific evaluations, where necessary, and implementing any necessary response actions.

EPA currently anticipates that there will be sufficient data to make a Human Exposure evaluation by 12/01/2025 because vapor intrusion investigations are anticipated to be completed by this time.