The maps of Massachusetts 21E sites on the BU SRP website have been updated. Massachusetts General Law, Chapter 21E, the state Superfund law, created the Waste Site Cleanup Program. Contaminated properties regulated under this law are commonly called “21E sites.” 21E sites are classified into tiers based on a variety of factors. These include the site's complexity, the type of contamination present, and the potential for human or environmental exposure to the contamination. Tier 1 sites require direct Department of Environmental Protection oversight during site investigation, remediation, and post-remediation monitoring.

The maps are based on data available on the website of the Massachusetts Office of Geographic and Environmental Information. In recent months, over 300 new 21E sites have been added and over 700 21E sites have been removed from the data set.