News of the Week says, "but it's too early for rave reviews of a policy developed in an atmosphere of political damage control in response to Congressional pressure." Environmentalists also view the new Bush Administration policy as a positive step, but would like to see the President take an even stronger stance. "We need to outline a faster timetable for negotiating an international treaty," says Rafe Pomerance, senior associate for policy affairs at the World Resources Institute. "We also need to put together a policy to reduce carbon dioxide emissions within the U.S., while simultaneously working out a strategy to get the other industrialized nations to join in." Pamela Zurer
OSHA takes new route to exposure limits The Occupational Safety & Health Administration's first formal attempt at mediated rulemaking has resulted in publication of a proposed rule limiting workers' exposure to 4,4'methylenedianiline (MDA), a hepatotoxin and potential human carcinogen, to 10 ppb averaged over eight hours. The current limit is 100 ppb. OSHA estimates that about 4000 workers are exposed to MDA. The agency expects the proposed standard to prevent from two to 23 cancer deaths per year, as well as reduce liver damage. Six U.S. companies produce about 605 million lb of MDA annually, according to OSHA, with 98% being used directly in the manufacture of methylenediphenyl diisocyanate, a component of urethane resins. The remaining 2% is used as a precursor in the manufacture of plastic fibers, antioxidants, dyestuff intermediates, and composite materials. OSHA says it will cost industry about $8.2 million per year to comply with the proposed standard. The proposed rule is based on the consensus recommendations of a committee, set up by OSHA in 1986, composed of representatives of three labor unions, three trade associations, California's OSHA, two national laboratories, and four fed6
May 22, 1989 C&EN
eral agencies. According to an OSHA spokesman, the mediated rulemaking was undertaken as part of an effort to speed up the issuance of health standards. That didn't quite work out. The committee presented its recommendations in May 1987. A proposed rule was supposed to be issued within six months, but it took two years. The Chemical Manufacturers Association, one of the participants in developing the consensus recommendations, found it to be a "very useful exercise," according to Betty Moran, who works on MDA issues for CMA. She explains that the committee held a series of seven meetings over the course of a year. Each meeting, run by a Department of Labor negotiator, was devoted to a single issue, such as the health effects of MDA, risk assessment, significance of the risk, or economic or technical feasibility. Developing a standard with input from all the interested parties is a very good process, Moran says, adding that CMA is committed to mediated rulemaking and would be quite willing to participate in such exercises in the future. Whether there will be any more mediated rulemakings is an open question. So far the one on MDA is the only one and OSHA doesn't have plans, at least right now, for any more. Janice Long
Transplant organs can be preserved longer The Food & Drug Administration has approved marketing of a solution that dramatically lengthens the time human livers and pancreases can be preserved before they are transplanted. Commercialized by Du Pont and called ViaSpan, the solution works by preventing swelling and enhancing the viability of cells within the organs. Previously, livers and pancreases had to be transplanted within about eight hours. Often emergency surgery had to be performed in the middle of the night by two teams, one for the donor and one for the recipient. ViaSpan will give medical teams one or more days to re-
ceive livers and pancreases, conduct lab tests, schedule surgery, and rest before operating. In addition to its effectiveness with livers and pancreases, ViaSpan matches the ability of previously available solutions to preserve kidneys for up to 40 hours. Heart and lung transplants will still require emergency surgery. However, Folkert O. Belzer, chairman of the department of surgery at the University of Wisconsin Medical School and coinventor of the solution, says he hopes the new technology will eventually be adapted so that hearts and lungs "can also be safely preserved for extended periods of time." Belzer's partner in the research effort was James H. Southard, a biochemist and associate professor of surgery at the medical school. Previous organ preservation solutions contained a phosphate buffer and a high concentration of a sugar, such as glucose. The sugar suppressed the tendency of cells to gain water and swell when stored in cold solution. These solutions were effective for preservation of the kidney, but not other organs. Therefore, says Southard, the team "began back in 1977 to look for chemicals that would effectively prevent cells from gaining water and would be nondamaging to tissue." The researchers found that a solution of lactobionic acid, in combination with a saccharide (raffinose), phosphate, and Pentafraction (hydroxyethyl) starch, prevents swelling for long periods of time. Other components of the new solution include adenosine, which helps cells generate energy immediately after transplantation; glutathione, which helps cells defend themselves against toxic cellular metabolites; and allopurinol, which inhibits one of the enzyme systems that generates these metabolites. "In partnership with Du Pont and the National Institutes of Health, Belzer and Southard have given us the gift of time," says Jimmy A. Light, former president of the American Council on Transplantation. "Organs will not only be preserved longer, they will be preserved better and will function more quickly after transplantation." St u Borman
