The EPA Misses Its Deadline to Finalize Dioxin Health Assessment

It's been 27 years since the EPA said it would issue a clear scientific report that could be used to set health-protective limits on dioxin in our food.


The Environmental Protection Agency (EPA) made a public promise to complete its assessment of the highly toxic chemical dioxin by the end of January -- two days ago. Deadline missed. Why does it matter? We, the people, need the federal government -- our government -- to issue a clear scientific report that dioxin is a highly toxic chemical so that state and federal regulators can use that to set health-protective limits on dioxin in our food, water, and environment.

So, why the delay? Since 1985 -- 27 years ago -- efforts by the EPA to assess the risks of dioxin have been delayed time and time again despite overwhelming scientific evidence supporting the EPA's assessment, and approval in 2010 by an independent Scientific Advisory Board (SAB). On August 29, 2011, the EPA announced its final plan for completing the Dioxin Reassessment. It then committed to completing the non-cancer portion of the reanalysis and posting it to its IRIS database by the end of this month, and to then complete the cancer portion of the re-analysis soon thereafter.

The hormone alterations and immune dysfunction increase risks of reduced fertility, birth defects, and cancer.

Now, the industry is in a lather over the EPA's imminent release of the non-cancer portion of its assessment, trying to get it to hold off on release until completion of its cancer assessment. However, after nearly three decades of work on dioxin, the EPA's procedural decision to issue the portion of the assessment it has completed will provide the public and regulators with a clear consensus statement on the most current estimated risk associated with dioxin exposure, and the supporting scientific evidence and rationale. Industry's disparagement of the EPA's release of the assessment in two parts as a "split-decision" makes about as much sense as criticizing J.K. Rowling for not waiting to complete all seven Harry Potter books before releasing the first one.

How bad is dioxin for my health? The term dioxin refers to a family of chemicals that contain one or more chlorine atoms attached to a double ring of carbon atoms. The most toxic and potent of the dioxins is 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD). High levels can cause liver damage and a host of other problems, most visibly including a skin condition called chloracne. However, animal and human studies show that even very low levels of 2,3,7,8-TCDD -- levels many people contain in their bodies today -- can cause a variety of health problems, including immunologic impairments and hormonal alterations. The hormone alterations and immune dysfunction increase risks of reduced fertility, birth defects, and cancer. For example, animal studies have found that the chemical can reduce sperm production, alter sex hormone levels, and increase miscarriage rates.

2,3,7,8-TCDD can also cause birth defects such as skeletal deformities, kidney defects, and learning and behavioral problems. More recent studies have found a potential link to increased diabetes risk. In 1997, the International Agency for Research on Cancer (IARC) determined that 2,3,7,8-TCDD was carcinogenic to humans (Group 1 [PDF]).

How might I be exposed to dioxin? Food is a significant source of dioxin exposure. Because dioxin accumulates in fat, the foods that contain the highest amounts are meat, dairy products, and fish. All people have some level of dioxin stored in their body fat, according to a representative sampling of people in the U.S. conducted by the U.S. Centers for Disease Control and Prevention (CDC). It takes at least seven years to excrete half of the 2,3,7,8-TCDD load, so clearing the body of the chemical takes a long time and most of us are being continually re-exposed through our diets.

What can I do? Children born in 1985 when the EPA started this assessment -- with dioxin in their bodies at birth -- are now 27, perhaps with children of their own, also born polluted with dioxin and hundreds of other toxic chemicals. Don't let the chemical and food industries stall the dioxin assessment for another generation. Urge the EPA to reject the latest wave of industry pressure to further stall the release of the dioxin reassessment and finalize the non-cancer portion of the re-analysis as quickly as possible.

Image: Matthias Pahl/Shutterstock.

This post also appears on NRDC's Switchboard, an Atlantic partner site.

Presented by

Jennifer Sass is a senior scientist at the Natural Resources Defense Council, where her work focuses on improving the regulation of toxic chemicals.

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