Policy News - November 26, 2003

EPA won't regulate dioxin in sewage sludge

The U.S. EPA announced on October 17 that it would not regulate dioxins in sewage sludge used as farm fertilizer, because new studies indicate that the human health and environmental risk from such usage is insignificant. The decision is a turnaround for the agency, which proposed in 1999 to limit dioxins in sludge—including chlorinated dibenzo-p-dixoin, chlorinated dibenzofurans, and coplanar polychlorinated biphenyls—to the toxic equivalent of 300 parts per trillion.

The agency released its decision on the day before a court-ordered deadline that required the government to resolve a decade-long controversy over the risk posed by dioxin in treated sludge. The deadline was part of an agreement settling a lawsuit filed by the National Resources Defense Council (NRDC), an environmental group. About 5.6 million tons of sewage sludge is produced each year in the United States, and more than 3 million tons is used as fertilizer. This land-applied sludge is a major source of dioxin exposure in the United States, second only to backyard trash burning.

NRDC’s Nancy Stoner, director of the group’s Clean Water Project, contends that EPA’s decision violates the Clean Water Act. Amendments approved by Congress in 1987 require EPA to set limits on pollutants in sludge, but the agency has not done this for dioxin or any other organic pollutant. “This decision shows the agency under this administration has forgotten its mission,” Stoner says.

EPA’s Geoffrey Grubbs, director of science and technology in the Office of Water, says that peer-reviewed studies conducted over the last five years show that dioxin levels in the environment have dropped dramatically because of tougher emissions limits for incinerators. Even in the worst-case scenario—a study of farm families that only consume food and dairy products from land fertilized with sewage sludge—minimal added risk was shown. Their risk is only 0.003 new cases of cancer in a year, or 0.22 new cases in 70 years.

EPA’s decision also cited an ecological risk analysis that, while more uncertain than the farm analysis, indicates that wildlife shouldn’t be significantly affected by exposure to dioxins in land-applied sewage sludge.

Some academic scientists, including David Carpenter, director of the Institute for Health and Environment at the State University of New York in Albany, question the government’s decision. Carpenter labeled the decision “irresponsible” given the fact that sludge is the second-greatest source of dioxin exposure in the United States. NRDC’s Stoner notes that dioxin is considered to be an endocrine disrupter and has been linked to negative immune and neurological system effects. EPA’s decision on sludge was published in the Federal Register on October 24, 2003. —REBECCA RENNER