Releases of oil and/or hazardous material to the environment are required to be reported to the Massachusetts Department of Environmental Protection's (MassDEP) Bureau of Waste Site Cleanup (BWSC), in accordance with M.G.L. Chapter 21E and procedures established within the Massachusetts Contingency Plan (MCP) (310 CMR 40.0000). The DEP Oil or Hazardous Materials Sites with Activity and Use Limitation (AUL) datalayer is a statewide point dataset containing the approximate location of oil or hazardous material release/disposal sites where an AUL has been filed. The sites mapped in this datalayer represent only a subset of the total reported release sites tracked by MassDEP BWSC. An AUL provides notice of the presence of oil and/or hazardous material contamination remaining at the location after a cleanup has been conducted pursuant to Chapter 21E and the MCP. The AUL is a legal document that identifies activities and uses of the property that may and may not occur, as well as the property owner's obligation and maintenance conditions that must be followed to ensure the safe use of the property. The complete AUL is filed at the County Registry of Deeds office for the respective City/Town. In addition, a copy of the AUL is available in MassDEP BWSC site files and in City/Town Offices where the AUL is located. Location types featured in this datalayer include the approximate center of an AUL site, the center of a building on the property where the release occurred, the approximate center of the lot, and source of contamination. Under Massachusetts' privatized waste site cleanup program, data maintained by DEP regarding site location is provided by potentially responsible parties (PRPs) and by licensed site professionals (LSPs), who work for the PRPs. Location data is provided in a paper format (e.g., map and textual information) by PRPs and LSPs and maintained by MassDEP BWSC in individual site files. These site files are available to the public through MassDEP's Regional Offices. Anyone wishing to view an AUL site file can make arrangements with the respective MassDEP Regional Office through a Freedom of Information Act (FOIA) request. The MassDEP encourages persons to review these site files when they make decisions that consider a specific site.