Certain industries in the United States which manufacture, process, use, or transport significant amounts of specific toxic chemicals (approximately 650 chemicals and chemical categories covering about 23,000 industrial and federal facilities) are required by law to report annually on the releases of these chemicals to the EPA (through its Toxics Release Inventory Program/TRI). TOXMAP maps on-site releases of these chemicals.
It should be noted that although facilities are required by federal law to use the best available data for their reporting, the accuracy of the reported data is unknown since it can be based on both actual measurements and on estimates. However, the Toxics Release Inventory is the best public information available on these chemicals.
The EPA Superfund Program is part of a federal government effort to decontaminate any land in the United States that has been contaminated by hazardous waste and that has been identified by the EPA as a candidate for cleanup because it poses a risk to human health and/or the environment. The program designates more than 800 substances as hazardous, and many more as potentially hazardous to human health or to the environment when improperly treated, stored, transported, disposed of, or otherwise managed. TOXMAP also maps Superfund chemicals and sites.
The toxic chemicals reported in this way make up only a small portion of the total amount manufactured, handled and used in the United States.
Industries are not the only entities responsible for toxic chemicals. Since the current reporting requirements apply only to industrial sources, sources of toxic chemicals from transportation, farming and households are not included. In addition, thousands of new chemicals are studied each year and thousands are manufactured. This number far exceeds the ability to test them all regarding possible toxic effects on people, plants or animals.