it and transferring it to a storage vessel, then later refilling the equipment after the maintenance has been completed. "With the technology and the equipment that's available on the market for SF6 recycling, there's absolutely no reason why a user of SF6 wouldn't have the ability to recover every bit," said Campbell. Manufacturers of electric switchgear have also made continual strides in rendering their equipment more leak-resistant according to Bolin of Mitsubishi Electric Power Products Inc Cigre an international organization associ-
ated with power production, has published a brochure on recycling SF6, and the National Electrical Manufacturers Association has created a working group on issues related to SF6. The magnesium industry is finding that it makes economic sense to reduce its SF6 use. Some of the incentive is coming from other industries that purchase their products. According to Maiss, Mercedes Benz has put pressure on European magnesium manufacturers, who use SF6 in magnesium processing, to dis-
because it adds too many C0 2 equivalents to their automobiles. In the United States, Chrysler is working with Hydro Magnesium, a major magnesium producer, to find an SF6 alternative, according to Scott Bartos, a program manager with an EPA Atmospheric Pollution Prevention project aimed at magnesium casters. Other efforts are underway in the magnesium industry. Two SF6 applications in Germany its use in filling tires and sound-proofing windows—have already been discontinued according to Maiss KELLYN S. BETTS
Models gauge pollution in environmental justice disputes EPA's Science Advisory Board is expected this fall to approve three modeling techniques designed to investigate environmental justice complaints, one of several tools being crafted to respond to an increasing number of petitions filed under Title VI of the Civil Rights Act. After a September public meeting, the Science Advisory Board's (SAB) Integrated Human Exposure Committee appeared ready to support the techniques, two of which are standard air emission models. But they criticized the limits of using Toxics Release Inventory (TRI) data and the models' weighting technique. "They told us they were scientifically defensible," said Ann Goode, chief of EPA's Office of Civil Rights. "Which is not to say perfect." EPA staff has begun altering the models said Goode. However the models do enable an ment of cumulative air pollution exposure something few models are designed to do EPA officials and outside agency observers said Citizen complaints alleging discrimination through the approval of permits are filed against state regulators; EPA must then investigate the complaint. Fifteen investigations are underway, and an additional 12 await processing, according to an August 13 Federal Register notice describing the models. Title IV prohibits the recipients of federal funds from discriminating on the basis of race color or national origin.
The techniques can determine whether emissions from a new facility will create a disparate pollution impact on a community. The agency employed two of the techniques, known as relative burden analyses, in its investigation of a much-publicized complaint filed against the Louisiana Department of Environmental Quality over a polyvinyl chloride plant planned for construction by Shintech Inc in 3. predominantly African American neighborhood in Louisiana The company with-
"Part of the problem is that [EPA] doesn't really have a policy yet" —Henry Anderson, chief medical officer, Wisconsin Department of Public Health drew its permit on Sept. 17, and plans to build a scaled-down facility closer to Baton Rouge, La. Under a 1994 executive order, all federal agencies must take steps to ensure their programs do not violate Title VI. Another EPA project, a Title VI guidance document designed for EPA, but released in February, was roundly criticized by state regulators who said it will radically affect their permitting and cleanup programs. Several state officials pect the same about the models
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Some environmentalists have criticized the models saying they are complicating a straightforward decision. "What EPA ought to follow is what we call the precautionary principle. If you see a situation that is already badly polluted, then don't issue a permit for a new facility that is going to pollute," said Damu Smith, the Greenpeace activist who spearheaded the national effort to prevent approval of Shintech's permit. The simple Basic Relative Burden Analysis calculates the average pollution burden for two population subgroups, usually African American and non-African American, that reside in proximity to the permitted facilities, according to an EPA staff paper. This basic analysis is easy to carry out—a plus considering the legally imposed sixmonth timetable for an investigation. The Enhanced Relative Burden Analysis can incorporate meteorological information and stack parameters and measures pollution in smaller units EPA staff did not use the third, more complicated and costly analysis, known as the Cumulative Outdoor Air Toxics Concentration and Exposure Methodology, during the Shintech investigation. But this technique, which analyzes outdoor emissions from many sources including nonpoint and mobile sources over large areas, would allow the agency to get to the heart of the complaints filed under Title VI said an EPA staffer who asked not to be named The citizen com-
plaints rely on the theory that the cumulative pollution in a particular area is already too much, the staffer said. Several SAB members criticized the definition of a pollution burden as too loose, said Don Barnes, SAB staff director. Because the analyses can determine the pollution burden, but they are not risk assessments, the burden cannot be explained as risk, and it does not represent exposure, he said. "The board felt EPA had to be careful about how burden was defined and communicated to the public," Barnes said. Other SAB committee members faulted the analyses for not considering chronic health effects such as asthma a top health problem in poor communities and instead focusing on anite health problems All three analyses rely on Toxics Release Inventory data. Although EPA staffers had to begin with known data, TRI reports do not really represent daily exposures, said Joe DiGangi, a Greenpeace toxicologist who attended the SAB review. The TRI summarizes annual emission estimates, but the company reports do not indicate when a chemical was emitted; they do not include all chemicals, such as dioxin; and they do not take into account chemical re-emission some committee members said. The multitude of chemical releases under the TRI (some 650 chemicals) makes establishing the burden difficult. To address this, the analyses weight the releases according to their toxicity, and the weighted chemicals are added together and treated as if they were one "pseudochemical." The pseudochemical framework involves too many assumptions, several committee members said. "The strength of this is that it covers many exposures, but does it really make scientific sense to combine cancerous and noncanceroi 1 s chemicals to come up with a load?" said Henry Anderson chairman of the SAB committee and chief medical officer for the Wisconsin Department of Public Health The committee suggested the chemicals be disaggregated into units of like chemicals to better indicate what was
driving the pollution burden, said Goode, and EPA staff have begun working on that suggestion. On the upside, all three models are transparent, so they would be easy to explain, said Anderson. They also use existing TRI and state data, and they do not take long to run to do [the investigation] in," he added. A separate committee concern dealt with how EPA might use the models, which is not SAB's bailiwick, admitted Anderson. "Part of the problem is that [EPA] doesn't really have a policy yet," Ander-
son said. "So we don't know what the outputs mean. EPA hasn't said what the magic number is that shows disparate risk." Six months ago, the civil rights office did not have these models, Goode said. "All of the environmental justice projects have presented the agency with a real challenge," said Goode. "We are working on how to get a grip on what our environmental requirements are and how they fit with our environmental justice concerns," she said. CATHERINE M. COONEY
International treaty aims to stem flow of toxics An international treaty signed in September by 57 countries, including the United States, establishes a "first line of defense" against unwanted imports of certain hazardous chemicals and pesticides, particularly in developing countries, according to Klaus Toepfer, executive director of the United Nations Environment Programme (UNEP). UNER together with the U.N.'s Food and Agriculture Organization, will oversee the treaty's implementation. Under the treaty, called the Rotterdam Convention on the Prior Informed Consent (PIC) Procedure for Certain Hazardous Chemicals and Pesticides in International Trade, any chemical that is banned or severely restricted in at least two participating countries cannot be exported without prior permission from the importing country. Through the information exchange facilitated by the treaty, importing countries will be able to decide which chemicals they want to receive and exclude those they cannot according to UNEP. If trade still takes place labeling requirements including information on any potential health and environmental effects should promote safe use The accord becomes legally binding only after 50 countries ratify it. As a first step among multilateral environmental agreements, however, governments have agreed to continue implementing the voluntary PIC procedure, in effect since 1992, with
the new provisions until the convention formally enters into force. Substances that fall under the PIC requirements include five industrial chemicals and 22 pesticides. Some of targeted chemicals are nearing the end of their useful life cycle—such as aldrin, dieldrin, and polychlorinated biphenyls— and some are still widely in use, such as DDT. Although DDT is banned in the United States, it is still the chemical of choice in many countries for controlling mosquitoes that carry malaria, said Cadileen Barnes widi EPA's Office of Pesticide Programs. "It happens to be a pesticide that's very cheap and not acutely toxic," she added. Acutely toxic pesticide formulations that present a hazard under conditions of use in developing countries, such as parathion and methyl-parathion, also are included on the PIC list. These two pesticides have caused a large number of accidental poisonings because their application restrictions are so stringent, said Jim Willis, UNEP's chemicals director. "But just because they're in PIC doesn't mean they can't be used safely," Willis added. "It just means mat these [importing] countries need to keep an eye out for them and make tiieir own decision on whether thev can use them safely" Many more substances are likely to be added to the list in the future according to UNEP. The chemical industry and environmental groups alike have applauded the accord as a step in the right direction to providing
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