EPA close to adopting tough lead-in-gas rule The Environmental Protection Agency's controversial off-again, on-again rule to further restrict the lead content of gasoline now appears to be final. The rule, proposed last week, is expected to go into effect Nov. 1, with one final public hearing scheduled for Sept. 7. Under the regulatory scheme set up by EPA in 1973, large refiners have been meeting a requirement that the average lead content of all gasoline produced, both leaded and unleaded, be 0.5 g per gal. Small refiners were to meet that requirement this October. Under EPA's new proposal, oil refiners would be allowed to add no more than 1.1 g of lead per gal in leaded gasoline because EPA found that as more unleaded gasoline was required for autos, refiners were raising the lead content of their leaded gasoline. Small refiners would be permitted to put up to 2.65 g of lead per gal in their leaded gasoline as they now do. However, only those small refiners, producing 10,000 barrels per day or less of gasoline, who were in existence as of Oct. 1, 1976, would be allowed to do so. This new definition of small refiners is expected to cut the number of firms in that category from 159 to 74. Taken together, EPA says these changes will reduce concentrations of airborne lead 31% more over the next eight years than would have happened if the current rules had remained in effect. The new proposed rule is very similar to the one leaked to the press earlier this month (C&EN, Aug. 9, page 4). This is in spite of lastminute pressure for changes exerted by the Office of Management &
Blanchard: disgusted but not surprised
Budget to the delight of environmental and public health groups who were most disturbed by the Reagan Administration's announcement a year ago that it intended to ease the lead-in-gasoline standard. Industry, which applauded that intention, isn't so happy with the rule that finally emerged. But as Lawrence E. Blanchard Jr., vice chairman of Ethyl Corp., says, "While we are disgusted with EPA's approach, we aren't surprised." He charges that EPA has "followed the same process of deliberately distorting the facts as it has for the past 12 years. As usual, [the agency] studiously [has] overruled every piece of evidence presented by industry and has accepted every claim by environmentalists." D
Cryogenic process recla ms scrap tires Various ways of dealing with the problem of scrap tire disposal have been tried: burning, destructive distillation, landfill, artificial reefs. A new facility in Indiana will be taking a different approach: cryogenic recycling. England Purchase Co.,Terre Haute, will use an Air Products & Chemicals process to reclaim 1 million automobile and truck tires per year. So far the firm has an agreement with General Tire & Rubber, Akron, to recycle rubber from scrapped tires collected by its stores and dealers. The magnitude of the problem— and of the recycling opportunity—is
great. Last year, 180 million passenger car and truck tires were sold in the U.S., all eventually destined to become scrap. In the Air Products process, chunks of tires from a shredder are sent through a freezing tunnel, where they are sprayed with liquid nitrogen at -320 °F. Embrittled, the chunks are ground into crumb rubber, typically with a hammer mill. The process uses about 8 lb of liquid nitrogen for each 20-lb scrap tire. About 95% of the rubber composition of a tire—14 or 15 lb of rubber from a 20- to 25-lb tire—is reclaimed. The rubber crumb result-
ing runs from 2 to 20 mesh. For basic mesh—that which doesn't require further grinding—direct manufacturing costs are in the area of 7 to 8 cents per lb. Rubber from the process can be used in a variety of products—among them, roofing materials and sealants, oil well linings, recreational surfaces, and asphalt paving. Recovered steel belting can be used in metal reclamation operations, and recovered fiber can be flame-proofed and used in insulation or padding materials. Interest in cryogenic recycling of tire rubber has been building for some time. For example, in the early 1970s, University of Wisconsin engineers, headed by mechanical engineer Norman R. Braton, worked with Cryogenic Recycling International Inc., La Crosse, to design a portable cryogenic recycling unit. Having been sold, the company is now Schriptek Recovery Systems Inc., and is heavily involved in preparing tires for rubber recycling. It is not now carrying out cryogenic processing but is working on development of that operation. D
Uniroyal copolymer challenges neoprene Competition among thermoplastic rubber producers to edge out neoprene as oil-resistant wire and cable insulation has intensified with the entry of Uniroyal's chemical division six months after the entry of Shell Chemical Co. The U.S. market for oil-resistant insulation totals about 50 million lb per year. This type of insulation finds use in such areas as on-site powering of heavy electrical equipment or hand tools by contractors, emergency power supplies, military power generation units in the field, and consumer outdoor power tools. Neoprene serves most of this market at present. The Uniroyal product is based on block copolymers of propylene and ethylene-propylene-diene monomer (EPDM). Shell uses block copolymers of styrene and ethylenebutylene. Cross-links needed for a rubber network form from crystallization of polypropylene segments in the Uniroyal product and polystyrene segments in the Shell entry. Such cross-linking is reversible on heating, which makes both rubber types thermoplastic. Both firms have actively marketed thermoplastic rubbers for other uses for many years. Shell has 275 milAug. 30, 1982 C&EN
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