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TRI National Analysis

Dioxins Releases by Industry

TRI also requires facilities to report data on 17 types, or congeners, of dioxin. These congeners have a wide range of toxic potencies. The mix of dioxins from one source can have a very different level of toxicity than the same total amount, but different mix, from another source. These varying toxic potencies can be taken into account using Toxic Equivalency Factors (TEFs), which are based on each congener’s toxic potency. EPA multiplies the total grams of each congener reported by facilities by the associated TEF to obtain a toxicity weight and sums all congeners for a total of grams in toxicity equivalents (grams-TEQ). Analyzing dioxins in grams-TEQ is useful when comparing disposal or other releases of dioxin from different sources or different time periods, where the mix of congeners may vary.

The following two pie charts show: 1) the TRI-covered industry sectors that reported the greatest releases of dioxin and dioxin-like compounds in grams, compared to 2) the industry sectors that reported the greatest releases of grams in toxicity equivalents (grams-TEQ). Note that only those TRI reports that included the congener detail for calculating grams-TEQ are included in these charts.


Note: Percentages may not sum to 100% due to rounding

  • Various industry sectors may dispose of or otherwise release very different mixes of dioxin congeners.
  • The chemical manufacturing industry accounted for 51% and the primary metals sector for 42% of total grams of dioxins released.
  • However, when TEFs are applied, the primary metals sector accounted for 81% and the chemical manufacturing sector for just 11% of the total grams-TEQ released.

This page was published in March 2019 and uses the 2017 TRI National Analysis dataset made public in TRI Explorer in October 2018.

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