Document 6kdZvMD3Ooo7MKDeXo53VpJm

UNION CARBIDE PLAINTIFF'S EXHIBIT ' "4 C0. ,-. 0 r; Ui. : u M* **% V/ bU p r. * i! . <- L 270 PARK AVENUE, NEW VOSX, NEW YORK 10017 .'ofs'sneJ Messrs: --py Jo C. Benjamin T. F. Frangos B. E. Godard J. Li. Myers J. A. Riddle N. J. Setter J. T. Sinclair J. R. Stickney W. S. Young uali Originating Dc?l. Ar.tvttlr.g Idler dale Suhjed April 3, 1969 Medical Department Asbestos iVEli W u- Nv* APR 7 1SS$ U.C.C. ch:m. & PLAST Gentlemen: Both because of changes in regulations and availability of data developed after the issuance of our report in 1964, Dr. Dernehl and I have revised the asbestos memorandum. A copy of the revision is enclosed. The major changes are the decrease in the Threshold Limit Value from 5 million particles per cubic foot of air to 2 million particles per cubic foot of air. (There is also a provision for another method of counting but it does not appear applicable to our short fiber asbestos.) We briefly discuss mesotheliomas, but data is too scanty as yet for a definite policy to be established. It is worth mentioning that the American Conference of Governmental Industrial Hygienists considered in 1968 a requirement that airline respirators be required for all contact with crocidolite asbestos. The resolution did not pass, but may come up again in future meetings. Any questions or comments will be welcome. Very truly yours, KSL:lk Enclosure K. S. 'Lane, M.Jfb. ~ " Assistant Medical Director S52ST0S TOXICOLOGY ?~.?C?:T It has been known for years that seme persons working in asbestos production were prone to develop a disabling lung disease. In time, this condition became known as asbestosis and was related to exposure to high concentrations of asbestos dust. With further experience, it was found that men could work with asbestos without development of lung disease if dust concentrations were kept below a cereain level. It has been generally accepted that a worker will not V. V lep asbestosis if he is exposed to no more than 5 million icles per cubic foot of air, even if this exposure con es for his entire working lifetime. Although no cases of wtosis are known to have occurred when exposures have maintained at or below this level, the ACC-IH (which sets threshold limit value (TLV) in the U. S. A.) has sated they intend to lower the TLV for asbestos to O r* * llion particles per cubic foot in an effort to increase safety factor incorporated in the limit. The U. S', rtmer.t of Labor has already issued a regulation under v/alsh-Heaiy Act placing the TLV for asbestos at 2 ion 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 2 bear; of light causing a Tyndall effect is present. Usually the dust concentration must be from 8-10 million particles per cuibc foot (MPPCF) before its presence it 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 asbeotosis. It is believed by most authorities that these eases have been associated with exposures significantly excseeing the Threshold Limit Value. A. type of cancer named mesothelioma has been noted to he assoc lamed with asbestos exposure in recent years. These tumors, while rather few in number to dace, may occur in individuals with histories of only slight exposures, and tn_t as .much as twenty to forty y^ars earlier. There is considerable evidence that crocidolise is most frequently associated with mesotheliomas. From the data available it appears that the TLV of 5 MPPCF is not low enough to protect against '.mesothelioma, and it is quite possible that 2 MPPCF is not, either. Research on the problem continues. Control of asbestos dust exposure is therefore necessary. The control methods are the standard ones applicable to a variety of dusty operations.They include closed flow systems. ;-;c; processes where possible, and adequate exhaust ventilation where openings in the system are necessary. Pelletizing is sometimes used to improve the handling characteristics 02" otherwise dusty materials. Where satisfactory containment to stay -within the Threshold Limit Value is impractical 1 or impossible, efficient and reliable respirators are available for the protection of the employee. A program 02" environmental monitoring is highly desirable to determine that Threshold Limit Values are r.ot being exceeded. In paper manufacturing, it would be desirable to know the dust con centrations where the asbestos is dumped from bags into the . pulp slurry. Concentrations should also be determined where dUi-._rg occurs in finishing products. While initial dust determinations should be made at frequent intervals, once the level has been established as satisfactory, the frequency may be extended to occasional tests to assure continuation of a satisfactory condition. Pro-employment and periodic physical examination of A -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 that no lung changes are- resulting from work with asbestos. It is believed that the addition of asbestos at the proposed levels during the manufacture, of paper products vroulc be harmless to the consumer. Total dusting would have 'jo bo well in excess oi any levels acceptable to the cor.r for the asbestos concentrations to approach the Threshold Limit Value. In conclusion, while asbestos bust in excess of the Threshold Limit Value is potentially harmful, as are many other 5 encountered in industry, it is as readily controlled as other such dusts and it can be used safely wish asorseriate orecautions. Industrial Kedieine And Toxicology Department Union Carbide Corporation UNION CARBIDE UitfCX CASSI3E CC?.?0RA71CN 270 PARK AVENUE, NEW YORK, N.Y. 10C17 ASBESTOS TOXICOLOGY REPORT It has been known for many years that seme persons working in asbestos production were prone to develop a disabling lung disease. In time, this condition became known as asbestosis and was related to exposure to high concentrations of asbestos dust. With further experience, it was found that men could work with asbestos without development of lung disease if dust concentrations were kept below a certain level. It is now gen erally accepted that a man can work a 40-hour week for a lifetime without developing asbestosis if the asbestos dust particle count is kept at or below 5 million particles per cubic foot of air. This dust concentration of 5 million particles per cubic foot of air is the Threshold Limit Value for asbestos, and no cases of asbestosis are known to have occurred when exposures have been maintained at or below this level, despite large-scale utilization {now approaching one miLlion tons per year in the U.S.A.). 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 must be from 8-10 million particles per cubic foot 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 major manufacturer of asbestos products who also mines asbestos has not been able to show an increase in cancerous growths in men working where dust concentrations were maintained at the Threshold Limit Value. Control of asbestos dust exposure is therefore necessary. The control methods are the standard ones applicable to a variety of dusty operations. They include closed flow systems, wet processes where possible, and adequate exhaust ventilation where openings in the system are necessary. Pelletizing is sometimes used to improve the handling character istics of otherwise dusty materials. Where satisfactory containment to stay within the Threshold Limit Value is impractical or impossible, efficient and reliable respirators are available for the protection of the employee. ' A program of environmental monitoring is highly desirable to determine that Threshold Limit Values are not being exceeded. In paper manufacturing, it would be desirable to know the dust concentrations where the asbestos is dumped from bags into the pulp slurry. Concentrations should also be determined where dusting occurs in finishing products. While Initial dust determinations should be made at frequent intervals, once the level has been established as satisfactory, the frequency may be extended to occasional tests to assure continuation of a satisfactory condition. -2- Pre-employment and periodic physical examinations of workers ar< desirable. These should include chest X-rays to insure that the worker has no chest condition prior to work with asbestos and to determine that no lung changes are resulting from work with asbestos. It is believed that the addition of asbestos at the proposed levels during the manufacture of paper 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 concentration to approach the Threshold Limit Value. In conclusion, while asbestos dust in excess of the Threshold Limit Value is potentially harmful, as are many other dusts encountered in industry, it is as readily controlled as other such dusts and it can be used safely with appropriate precautions. Carl U. Dernehl, M. D. Director of Toxicology K. S. Lane, M. D. Assistant Director of Toxicolog;