Flooding from the dioxin-contaminated Tittabawassee River has polluted the soils at Saginaw Township's West Michigan Park. (Photo: Michigan Messenger)

The U.S. Environmental Protection Agency said this week that it will try to speed the release of its reassessment of dioxin, a chemical that has contaminated Michigan’s largest watershed.

Dioxin, a by-product of the chemical manufacturing process, has long been known as a carcinogen and is regulated by state and federal agencies. EPA studies of the chemical since 1991 have indicated that the substance is far more toxic that previously thought (pdf) — capable of damaging the endocrine and immune systems and changing fetal development at common background levels — but political pressures have delayed the official release of these findings.

“The new administration is familiar with the history of this issue and will be focusing on expediting the study,” EPA spokeswoman Suzanne Ackerman said this week.

“We’re pleased to hear EPA plans to expedite the study,” said Mike Schade of the Virginia-based Center for Health, Environment and Justice, which together with 100 other groups sent a letter to the Obama administration in late January asking that the dioxin reassessment be released.

“As a first step, EPA should cancel the unnecessary [Science Advisory Board] review and release the Dioxin Reassessment so that the EPA and others can move forward in developing protective dioxin policies and standards.”

Schade said that a further review of the report, which has existed in draft form since the early ’90s, would delay the release of the report for years.

“While panels are convened,” he said, “people in communities across the country are continued to be exposed to this highly toxic chemical.”

Last year the Government Accountability Office recommended that the EPA adopt a streamlined process for completing the dioxin study but noted that the Bush administration EPA chose not to adopt its proposal.

In a January report to Congress the Government Accountability Office said that EPA’s delays in releasing the dioxin reassessment pose a high risk for public health. The agency wrote:

Although dioxin is a known cancer-causing chemical to which humans are regularly exposed by eating such dietary staples as meats, fish, and dairy products, actions to protect the public will likely be delayed until the assessment is complete. Since EPA estimates that the assessment process for complex chemicals such as dioxin could take 6 to 8 years to complete, the public in the meantime will likely remain at risk.

In Michigan, operations at Dow Chemical’s Midland plant have contaminated 50 miles of the Saginaw Bay watershed with dioxin.

Last week EPA announced a freeze on cleanup negotiations with Dow that were begun in the final days of the Bush administration and which were criticized for lack of transparency. Also last week, Dow announced that it would remove dioxin contamination at Saginaw Township’s West Michigan Park.

Dow also appeared in the State Supreme Court, which is expected to rule on whether an environmental class action suit against the company can proceed.