TRI Reporting of Dioxins - What is Meaningful and What is not?

PCDD/Fs are an unintentional source byproduct of certain industrial, non-industrial and natural processes, usually involving combustion. When assessing the TRI dioxin figures that are reported by the US EPA, it is essential to distinguish between two numbers - the amount of PCDD/Fs that are generated vs. the amount of PCDD/Fs that are released into the air, water or land. Much of the PCDD/Fs that are generated is responsibly disposed of in a sound manner and is not released into the environment.

When compared to other EPA dioxin source inventories, the TRI is likely to show what might appear to be high levels of industrial PCDD/F releases. For the following reasons, the TRI report will reflect inflated figures, not increased pollution:

  • Only a small percentage of the PCDD/Fs that are released in generated in industrial production is ever released to the environment. This is because industry carefully treats and disposes of the vast majority of its dioxin byproducts in an environmentally responsible manner. These treatment methods include disposal to specially designed hazardous waste sites and sophisticated incineration techniques that destroy PCDD/Fs almost completely.

  • The US EPA TRI reporting format includes the figures for both the on-site treatment and destruction of PCDD/Fs to which the public is never exposed, as well as the smaller amounts of this compound that are released to the environment. This reporting requirement creates the potential for confusion and unwarranted concern about seemingly high figures that, in fact, do not constitute an exposure, much less a threat to the public’s well-being.

  • Canada, by contrast, uses a reporting format that conveys a more accurate picture of PCDD/Fs releases.  The Canadian reporting format provides data in toxic equivalency basis (TEQ), a method of measurement that weights PCDD/Fs compounds according to their toxicity.  It should be noted that TEQ is an internationally recognized method that is currently used by the World Health Organization as a means of measuring the toxicity of these compounds. 

  • The U.S. EPA Toxics Release Inventory treats all PCDD/Fs as if they are equally toxic, which they are not. The vast majority of all industrially produced PCDD/Fs are of the least toxic varieties, most of which are up to 10,000-times less toxic than 2,3,7,8-TCDD, the form of PCDD/Fs considered to be the most toxic.

  • U.S. EPA data clearly show that the chlorine chemistry industry is not a significant source of PCDD/Fs releases to the environment.  Yet, many significant sources of PCDD/Fs are not included in the U.S. EPA’s TRI.  These unreported sources include forest fires, backyard burning, and diesel exhausts.
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