Document nkpjGVvLa5w0n59b0przvdMM6

cc if (<? ASBESTOS TOXICOLOGY REPORT PLAINTIFFS EXHIBIT UC-1996 It hat been knovn for years chat some persons working In asbetcos production were prone to develop a disabling lung disease. In tine, this condition became known as asbetcosls and was related to exposure to high concentrations of asbestos dust. With further experience, it was found chat sicn could work with asbestos without development of lung disease if dust concentrations were kept below a certain level. It has been generally accepted that a worker will not develop asbestosis if he is exposed to no more chan 5 million particles per cubic foot of air, even if this exposure continues for hie entire working lifetime. Although no cases of asbestosis arc knovn to have occurred when exposures have been maintained at or below this level, Che ACCIH (which secs the threshold limit value (TLV) in the U. S. A.) has Indicated they intend to lover the TLV for asbestos to 2 million particles per cubic foot in an effort to increase the safety factor Incorporated in the limit. The U. S. Department of Labor has already Issued a regulation under the Valsh-Hesly Act placing thi TLV for asbestos at 2 million particles per cubic foot for public contracts in which they have jurisdiction. This concentration of dust is generally not visible in the average work area unless a beam of light causing a Tyndall effect: is present. Usually the dust concentration siuac be from 5-10 million particles per cubic foot (KPPC7) before its presence is visible in average lighting conditions. Several years ago, it was reported that there was an Increase In the incidence of cancerous tumors, especially of the lung, associated with asbestosis. Recently there have been reports of some cancers occurring In individuals exposed to asbestos dust, but who have not developed clinical asbestosis. It is believed by most authorities that these cases have been associated with exposures significantly exceeding the Threshold Limit Value. A type of cancer named mesothelioma has been noted to be associated with asbestos exposure in recent years. These tumors, while rather few in number to date, may occur In individuals with histories of only slight exposures, and that as much at twenty to forty years earlier. There Lai considerable evidence that erocidollte la most frequently associated with mesotheliomas. From eht data available it appears that the TLV of 5 KFPCF may not be low enough to protect against mesothelioma. Rasearch on thn problem continues. D.li fk-L, DEPQ. EXH.j- KIRBY A. KENNEDY COURT REPORTER UNION CARBIOE CORPORATION CHEMICALS AND PLASTICS 270 PARK AVENUE. N.Y..N Y. ICC 17 ir zc t..:-. f.c fi:::,:-: cr.: c: vc.: i. c: They Include closed flow syetems, wet processes where possible, r.d adequate exhaust ventilation where openings In the system ere necessary. Pellecizing Ls sometioes used to improve the handling characteristics of otherwise dusty materials. Where satisfactory containment to stay within the Threshold Licit Value is impractical or impossible, efficient and reliable respirators are available for the protection of the employee. A program of environmental monitoring la highly dealrable to determine that Threshold Limit Values are not being exceeded. In manufacturing Industries it would be desirable to knew the dust concentrations where the asbestos is dumped from bags into Che process. Concentrations should also be determined where dusting occurs in finishing products. While initial duat determinations should be made at frequent intervals, once the level has bean established as satisfactory, the frequency may be extended to occasional testa to asaure continuation of a satisfactory condition. Pre*employment end periodic physical examination of workers are desirable. These should include chest X-rays to insure that the worker has no chest condition prior to work with asbestos and to determine chat no lung changes are resulting from work with asbestos. It is believed that Che addition of aabestoa at the proposed levels during the manufacture of products would be harmless to the consumer. Total dusting would have to be well in excess of any levels acceptable to the consumer for the asbestos concentrations to approach the Threshold Limit Value. Zn conclusion, while asbestos dust in excess of the Threshold Limit Vtlue is potentially harmful, at are many other dusts encountered in industry, it is as readily controlled as ocher auch dusts and it can be used safely with appropriate precautions. 5/8/69 Industrial Medicine And Toxicology Department Union Carbide Corporation