General Information

TOXMAP® ( is a Geographic Information System (GIS) from the Division of Specialized Information Services of the US National Library of Medicine® (NLM) that uses maps of the United States to help users visually explore environmental health data from the US Environmental Protection Agency (EPA)'s Toxics Release Inventory (TRI) and Superfund Program, as well as several non-EPA datasets.

The current version of TOXMAP, developed with the Esri® Web AppBuilder, replaces both previous versions of TOXMAP, including TOXMAP classic and the newer Flash-based version of TOXMAP. This version does not require any additional browser plug-ins and runs on tablet and mobile devices.

For more information, see the TOXMAP Fact Sheet.

The effect a chemical has on a living organism-- if any-- is called the organism's response. The response is related to the chemical dose and to the resulting concentration of the chemical in the organism. The dose of a chemical often determines the extent of the effect it produces. Understanding the dose-response relationship is necessary for understanding the cause and effect relationship between chemical exposure and illness.

The toxicity of a substance depends on many factors: the form and chemical activity; the dosage, especially the dose-time relationship; exposure route; species; age; sex; ability of the chemical to be absorbed; metabolism; distribution within the body; excretion; and the presence of other chemicals.

The variety of responses among organisms that get the same dose of chemical is due to individual susceptibility. Dose and individual susceptibility play roles in all situations involving chemical exposure. Toxicologists study responses of living organisms to doses of chemicals.

Always keep in mind that the co-occurrence of a substance and a particular health problem does not by itself imply an effect on human health by that substance; the association of two or more variables (correlation) does not, by itself, imply a cause and effect relationship.

You can learn more about chemicals and toxicity with this Toxicology Tutorial, which covers basic toxicology, organized by chapter and offering text, graphics, and quizzes/assessments.

It is difficult to answer this question simply because there is currently no standard approach to assess overall human health risk. People are exposed to chemicals in our environment via in the air we breathe, the water we drink, the houses we live in, and the food we eat. TRI releases and Superfund sites are just a few examples of sources of chemical exposure.

Some of these chemicals may affect our health. Understanding exposure and determining whether there is a health risk is a very complex process. There are many factors that affect health risk. A large release of one chemical might be less harmful to our health than a smaller release of another chemical; the impact of air releases can be affected by wind direction and other factors.

Learn more about chemicals and risk to human health with the links below:

At this time, TOXMAP uses reported on-site releases only. Some TRI chemicals have no reported releases, and so will not appear in the TRI release data or in TOXMAP.

Certain industries in the United States that 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). TOXMAP maps on-site releases of the listed chemicals covered by the EPA TRI program.

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.

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. It is not possible to test each chemical regarding possible toxic effects on people, plants or animals.

The data found in TOXMAP comes from several providers, including:
  • Toxics Release Inventory (TRI)

    A federal law called the Emergency Planning and Community Right to Know Act (EPCRA) requires facilities in certain industries which manufacture, process, or use significant amounts of toxic chemicals, to report annually on their releases of these chemicals. The reports contain information about the types and amounts of toxic chemicals that are released each year to the air, water, land and by underground injection, as well as information on the quantities of toxic chemicals sent to other facilities for further waste management.

    Facilities with ten or more full-time employees that process more than 25,000 pounds in aggregate, or use greater than 10,000 pounds of any one TRI chemical, are required to report releases annually. The US Environmental Protection Agency (EPA) maintains this information in a database called the Toxics Release Inventory (TRI). The toxics release files on the National Library of Medicine's® (NLM) Toxicology Data Network (TOXNET®) come from TRI.

    TOXMAP uses the TRI data from the 2016 National Analysis dataset. NLM TOXNET uses the most current TRI data. Data submission deadlines, data entry processes, and data quality control and review all influence the actual date of data release by both the EPA and by TOXNET. A complete list of TRI chemicals required to be reported to the EPA can be found at their TRI-Listed Chemicals page.

    NOTE: At this time, TOXMAP uses reported on-site releases only. Some TRI chemicals have no reported releases, and so will not appear in the TRI release data or in TOXMAP.

    For more information, see the TRI Fact Sheet.


    CERCLIS contains information about Superfund sites, such as the current status of cleanup efforts, cleanup milestones reached, and amounts of liquid and solid media treated at sites on the National Priorities List (NPL) or under consideration for the NPL. The CERCLIS database can be searched online.

  • US Census

    TOXMAP Census data from 2000 and 2010 comes directly from the US Census. This includes selected county-level demographics (age, male/female ratio, population and race/ethnicity) and can be found in its original form on the US Census Bureau's website. TOXMAP's Native Lands layer is also comprised of data from the US Census.

  • National Cancer Institute SEER

    TOXMAP uses the NCI's SEER*Stat database for its cancer and disease mortality data. Underlying mortality data is provided by the NCHS, part of the US Department of Health and Human Services.

  • EPA's Air Markets Program Data (AMPD)

    AMPD is a publicly-available data system from the EPA Clean Air Markets program for searching and downloading data collected as part of EPA's emissions trading programs. TOXMAP displays all facilities in all programs covered in the AMPD in 2017 whose primary or secondary fuel type is coal-related (e.g., Coal, Coal Refuse, and Petroleum Coke).

  • Energy Information Administration (EIA)

    Coal plants in TOXMAP link to their associated record in the EIA Electricity Data Browser.

  • EPA's Facility Registry System (FRS)

    TOXMAP plots the location of TRI facilities using addresses and coordinates from the EPA's Facility Registry System (FRS). The FRS is a centrally managed database that identifies facilities, sites or places subject to environmental regulations or of environmental interest.

  • Hazardous Substances Databank® (HSDB)

    HSDB contains comprehensive toxicological information on more than 4,700 chemicals. Data in HSDB are peer-reviewed, and are derived and referenced from a core set of books, government documents, technical reports and selected primary journal literature. For more information, see the HSDB Fact Sheet.

  • The Bureau of Economic Analysis (BEA)

    The BEA, part of the US Department of Commerce, publishes the per capita personal income data used by TOXMAP.

  • National Atlas of the United States of America (USGS)

    TOXMAP used the USGS's National Atlas (now part of The National Map) for 1990 county-level demographics (age, male/female ratio, population and race/ethnicity) and can be found in its original form on the US Census Bureau's website.

  • Environment and Climate Change Canada

    Environment and Climate Change Canada publishes data from the NPRI, Canada's legislated, publicly accessible inventory of pollutant releases (to air, water and land), disposals and transfers for recycling.

  • Nuclear Regulatory Commission

    The Nuclear Regulatory Commission publishes the commercial nuclear power plant data found in TOXMAP.

  • Esri

    All basemaps (Streets, Topographic, Aerial) come from Esri, as do congressional district boundaries.

TOXMAP facility locations are calculated by an estimation process that relies on "geocoding." Geocoding is a method that assigns latitude and longitude to an address. Even the most accurate latitude/longitude coordinate calculations, including those used by TOXMAP, are estimates; this can account for minor inaccuracies in site locations on a map.

Addresses are geocoded using software that accesses location information from a variety of sources which contain street segments; address ranges are attached to each side of the segment. TOXMAP's geocoding program estimates the location of each facility address based on this address range. Although very accurate, these locations are estimates, and they should not be used to definitively locate a particular facility.

For more information about the accuracy of locations in TOXMAP, see "How accurate are TRI locations in TOXMAP?"

Although TOXMAP is not specifically designed for any one particular group, the TRI and Superfund Programs can be of interest to specific populations such as Native Americans by helping to find sources of chemical releases and contamination in locations of interest to them. For instance, in TOXMAP click "Enter location" search box, type in a place of interest like an Indian reservation, then click the magnifying glass to search. You can also save the location for later use by clicking the "Bookmark" icon in the toolbar, then use this named "bookmark" to zoom to that location for quick reference later in your session.

The TOXMAP Native Lands map layer shows geographic areas of certain native populations, including American Indian Reservations and Off-Reservation Trust Lands, Alaska Native Village Statistical Areas, and Hawaiian Home Lands, as defined by the US Census. This layer can be toggled on and off via the Map Contents side panel.

You can also overlay US Census data by race: "American Indian and Alaskan Native" (1990), "One Race: American Indian and Alaska Native" and "Two or more races including: American Indian" (2000), or "American Indian" (2010).

For more information, see the TOXMAP and Native American Populations page.