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TRI National Analysis

Releases of Chemicals in the 2016 TRI National Analysis

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Helpful Concepts

What is a release?

In the context of TRI, a “release” of a chemical generally refers to a chemical that is emitted to the air, discharged to water, or placed in some type of land disposal unit.

Disposal or other releases of Toxics Release Inventory (TRI) chemicals into the environment occur in several ways. Chemicals may be disposed of on a facility’s property by being released to the air, water or land. Facilities may also ship (transfer) wastes that contain TRI chemicals to an off-site location for treatment or disposal. Note that most disposal or other release practices are subject to a variety of regulatory requirements designed to minimize potential harm to human health and the environment. To learn more about what EPA is doing to help limit the release of TRI chemicals to the environment, see EPA's laws and regulations webpage.

Evaluating releases of TRI-listed chemicals can help identify potential concerns and gain a better understanding of potential risks that may be posed by the releases. This evaluation can also help identify priorities and opportunities for government and communities to work with industry to reduce chemical releases and potential associated risks. However, it is important to consider that the quantity of releases is not an indicator of potential health impacts posed by the chemicals. Human health risks resulting from exposure to TRI chemicals are governed by many factors, as discussed further in the Hazard and Risk of TRI Chemicals section.

Many factors can affect trends in releases at facilities, including production rates, management practices, the composition of raw materials used, and the installation of control technologies.

The following graph shows the disposal or other releases of TRI chemicals, including on-site disposal to land, water, and air, and off-site transfers for disposal.


From 2006 to 2016:

From 2015 to 2016:

  • On-site air releases, on-site surface water discharges, and off-site disposal decreased while on-site land disposal increased. Total releases to the environment increased by 1%.

Releases in 2016

Use the interactive chart below to explore how total releases of chemicals that occurred in 2016 are associated with different industry sectors, specific chemicals, and geographies. Visit the full TRI National Analysis Qlik dashboard to explore even more information about releases of chemicals.

Releases by Chemical

Release quantities of 8 chemicals comprise 73% of total releases.


Note: In this figure, metals are combined with their metal compounds, although metals and compounds of the same metal are usually listed separately on the TRI list (e.g. lead is listed separately from lead compounds).

Releases by Industry

The metal mining sector accounts for 44% of releases (1.52 billion pounds), which were primarily in the form of land disposal.


This page was published in January 2018 and uses the 2016 TRI National Analysis dataset made public in TRI Explorer in October 2017.

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