The U.S. Environmental Protection Agency is moving closer to its goal of releasing an updated estimate on the potential harm of dioxin exposure by the end of the year.

In May, in a long-stalled response to concerns raised by the National Academies of Sciences in 2006, EPA reaffirmed its position that dioxin causes cancer and other negative health effects even at extremely low levels of exposure and stated that most Americans are being exposed to unsafe levels of the chemical through the foods that they eat.

Stephen Lester, science director for the Center for Health Environment and Justice is in the process of reviewing EPA’s 1,850 page document .

“EPA is standing behind its analysis that shows dioxin causes adverse health hazards at very low levels,” Lester said. “We would say it is a serious public health hazard.”

“Food is the primary means of exposure for the general public,” he said, and “roughly 90 percent of general population is exposed to dioxin through food, primarily beef and dairy.”

For the first time in this report EPA has named a level of dioxin exposure at which no adverse health effect is expected to be observed, Lester said, but this level is so low that it indicates that most Americans are already receiving more than is safe.

EPA’s actions on dioxin are of particular importance in Michigan, which is home to the headquarters of the Dow Chemical company. Operations at Dow’s Midland facility have resulted in dioxin contamination of the city of Midland and of a 52 mile long stretch of the Saginaw River watershed.

New understandings on the health effects of dioxin could affect the type of cleanup that happens in this area and the type of assistance offered to those living in the contaminated zone.