Document 3edXLk8zwB6vdan8wrrkNR4D6

mr/riia^Hj:<=M!Bgg U.S. firms still use it, despite its checkered career 8-h, time-weighted basis, with a 15ntin ceiling of 5 fibers/cm5. All limits apply only to fibers longer than 5 ftm. The term "asbestos" comprises a group of impure magnesium (MOSH, which serves in an advisory i silicate minerals--e.g., chrysotile, amosite--that occur in fibrous form. capacity, has recommended a limit of Reports of the toxic properties of asbestos date back to the 1920s in 0.1 fiber/cmJ.) the U.S. However, it wasn't until the war broke out, when millions of OSHA is currently evaluating the i workers were employed in shipyards insulating warships, that mass economic impact of the proposed stan exposure to asbestos dust occurred in this country. dard, which is bound to affect both The material enjoyed wide popularity as an insulator in plants and processing and use of the material. buildings until 1970, when, in response to mounting evidence of its Predictably, industry reponse to the toxic properties, manufacturers stopped producing insulation made of idea has not been favorable, aia calls loosely bound asbestos fiber. the 0.5-fiber/cmJ limit "not technical The Asbestos Information Assn, says that the 3,000 asbestos ly feasible," and recommends instead products made today in the U.S. contain chemically and physically the adoption of 2 fibers/cm5 as a bound fibers that do not flake ofT. Current end-use breakdown: asbestos cement products (pipe, sheets), 22.4%; roofing products, 34.9%; asbestos paper, 4.3%; flooring products, 15.6%; packing and gaskets, 2.8%; thermal and electrical insulation, 1.2%; friction permanent standard--one that can be realized at a reasonable cost for dust control. On the other side of the spectrum, 5 i \ products (brake linings), 8.8%; coalings and compounds, 2.7%; Roy Steinfurth, the asbestos workers' X plastics, 3.0%; textiles, 1.0%; and miscellaneous, 3.3%. i spokesman, feels that the only accept r j able level is no asbestos exposure at all. i The union official says that, even if the i outbreak of asbestos-related diseases leading maker of asbestos products): exposure level is reduced to 0.5 i among World War II shipyard work "Clinical evidence shows that lung fiber/cm5, a worker would breathe in ers, explains that such a heavy expo cancer in asbestos workers is virtually 4 million fibers in an 8-h workday. He sure to asbestos existed before medical limited to those who smoke cigarettes, estimates that as many as 50% of the information revealed the dangers in and that for practical purposes, lung members of his organization will even volved. Since then, millions of dollars cancer as an asbestos-related disease tually die of asbestos-related diseases. have been spent in dust-control equip would not be a problem were it not for In Europe, there is also a move to ment by miners, millers, processors cigarette smokers." cut down on the exposure level, which * i and manufacturers of asbestos. A1A is currently on a vigorous has been 2 fibers/cm5 in the past few In addition, note other asbestos- campaign to persuade industry work years. Italy, which lacks asbestos industry spokesmen, the type of prod ers to stop smoking. deposits, is attempting to phase out the i ucts made in the past--e.g., asbestos "There is no doubt that exposure material completely. Sweden moved to thermal insulation--are no longer and cigarette smoking have a synergis a 1-fiber/cm1 standard a year ago, I produced. They were phased out in tic effect," says an ACS spokesman, and U.K. authorities are clamoring for the early 1970s, when the inherent "but since so many workers included a reduction of the present limit. hazards became apparent (see box). in past studies were smokers or ex Critics who complain that the OSHA Nevertheless, asbestos is still used as smokers, it's difficult to assess the risk proposal does not go far enough in an insulator or fire retardant in more to non-smokers." protecting workers also question why & i than 3,000 products ranging from The synergism is acknowledged in the standard should apply only to r water pipes to brake linings. And an the WHO document. "Both cigarette fibers longer than 5 ftm. Both SelikofT estimated 500 million tons of the mate smoking and exposure to asbestos and Wagoner, for example, believe rial are still around in plants and independently cause lung cancer. that the smaller fibers are even more s'.- buildings throughout the U.S., accord ing to Roy Stcinfurth, administrator of the insulation health-hazards pro However, when present together, they act in a multiplicative fashion." The NCI/MEHS study agrees, and admits active in producing lung tumors. And, according to SelikofT, "For each fiber longer than 5 jem, there may be as jf grams for the International Assn, of that it would be an error to attempt to many as 100 shorter ones." Heat and Frost Insulators and Asbes blame each type of cancer mentioned OSHa's Health Standards Project tos Workers (Washington). Workers in the report on an exclusive cause. Officer William Warren says that the still exposed to asbestos are not A NEW STANDARD?--The current 5-#tm length was the most practical adequately protected, charges SelikofT. flareup of the asbestos controversy is of alternative because detection equip CIGARETTE link--Industry spokes more than marginal interest to OSHa, ment does not pick up anything small men also point out that exposure to which has been trying to modify pres er. Warren notes that available moni asbestos alone may not be enough to ent rules governing exposure to the toring units detea only "from a few cause lung cancer--the disease most material (the agency is studying the percent to 50%'' of the actual number commonly associated with the breath NCI/K1EHS report). of fibers in a sample. ing of asbestos fibers--and that the For more than three years, OSHA INSULATION DANGER --Spot checks connection between exposure and ciga has been pushing a proposal to reduce with a number of U.S. insulation rette smoking has not been stressed the permissible level of airborne fibers manufaaurers turned up no one still enough. Says John A. McKinney, in the workplace from a present vhlue making the asbestos-containing ver president of Johns-Manville Corp. (a of 2 fibers/cm1 to 0.5 fiber/cm1 on an sion. However, there are still tons of it P 78 CHEMICAL ENGINEERING NOVEMBER 6. 197B FOS 0007189