Sweeping court decision could crush smog plans, rein in TRI and wetlands rules Two U.S. Court of Appeals decisions that remanded EPA's new particulate matter (PM) and ozone standards to the agency have starded those involved with the programs. The orders could immediately stop EPA's far-reaching plan to control smog. And if a current appeal to overturn the ruling does not succeed, the opinion might spur a review of other programs, including the Toxics Release Inventory (TRI) and the wedands protection program. In the short run, the May 14 decision from the U.S. Court of Appeals for the District of Columbia Circuit will prevent EPA from enforcing the PM and ozone standards. While die ruling did not overturn the 1997 standards, as the array of industry-driven lawsuits had sought, it did send them back to EPA asking officials to better justify the levels set (American Trucking Associations Inc. v. EPA).
Several lawyers representing electric power companies—expected to be targeted by states for controls on the smog-precursor nitrogen oxide (NOx)—noted that the May 14 ruling, and a May 25 order by the same judges, could ultimately squash the agency's efforts to reduce urban smog. "It is clear that these two decisions have caused EPA to completely restructure its entire approach to controlling NO., from Midwestern power plants," said David Flannery, director of the Midwest Ozone Group, a Midwestern utility organization. The May 25 judgment put an indefinite hold on the NOx state implementation plan (SIP) call (ES&T, 1997, 31(1) 555A), an initiative that required 22 states to submit NO.,. plans to help northeastern states comply with the one-hour ozone standard. Taken together, the rulings
forced EPA officials to redirect the focus of the smog control program to die one-hour standard, the attorneys said. As a safeguard, most northeastern states filed petitions with EPA under Section 126 of the Clean Air Act (CAA), asking the agency to shut down specific pollution sources contributing to their inability to meet federal ozone rules. Some states based their petitions on the now remanded eighthour ozone standard; others on the one-hour, said Jeff Clark, with EPA's Office of Air Quality Planning and Standards. In June, EPA asked the court to withdraw the state petitions, distancing the petitions from the court's order. A new rulemaking, due Nov. 30, will resurrect the state petitions based on the onehour standard, Flannery said. However, power plant attorneys are not sitting on their hands. They have already sued EPA, challenging its reliance on the state petition process. "EPA's actions leave open the question of whether Section 126 is valid to
HEALTH NIOSH study of chemical workers bolsters data on dioxin as cancer agent A new study of chemical workers exposed to high levels of dioxin clinches its standing as a confirmed human carcinogen by strengthening the quality of data on human exposure to dioxin, according to several researchers. The analysis, by Kyle Steenland and coworkers at the National Institute of Occupational Safety and Health in Cincinnati, Ohio, concludes that chemical workers exposed to high levels of dioxin have a 60% increased risk of dying of cancer compared with the general population and a higher rate of heart disease when compared with workers exposed to lower levels of dioxin. Published in the May 5 issue of the Journal of the National Cancer Institute, the study involved the largest group of workers ever exposed to dioxin. It "really clinches" dioxin's standing as a confirmed human carcinogen, because the study zeroed in on workers' exposure, said EPA toxicologist Linda Birnbaum, who spe-
cializes in dioxin and dioxin-like compounds. In 1997 the World Health Organization's International Agency for Research on Cancer listed 2,3,7,8TCDD as a known human carcinogen on the basis of unequivocal animal data, strong mechanistic information, and relatively weak data on humans (£S(Sri998, 32(13), 302A). Although this new study strengthens the human data, it says nothing about the risk of cancer from low doses of dioxin. "For low doses, we have to rely more on laboratory results and understanding mechanisms," said Robert Hoover with the National Cancer Institute, in Bethesda, Md. The analysis also says nothing about risks specific to women. The researchers analyzed data concerning 5132 men who worked at 12 U.S. chemical plants from 1942 to 1984. Using blood samples from 250 of these workers, they calculated that the men had an average blood dioxin level of 2000 parts per trillion, 100 to 1000 times higher than the
general population. When other dioxin-like compounds are included in the comparison, the worker's exposure levels are 10 to 100 times those of the general population, according to Birnbaum. Although this group of workers has been the subject of many studies, the quality of the exposure estimates is excellent in the new analysis, said Birnbaum. These estimates take into account each person's specific job, details about each plant, and how many hours a day each man worked. The finding that high levels of dioxin exposure increase the risk of all cancers combined fits with current understanding about dioxin's mechanism of toxicity, said Birnbaum, adding that animal studies indicate that dioxin promotes growth in existing cells. The observed increase in heart disease, although not as strong as dioxin's link with cancer, is also consistent with other work. —REBECCA RENNER
AUGUST 1, 1999 /ENVIRONMENTAL SCIENCES TECHNOLOGY/ NEWS • 3 0 7 A
