Document YrdD06n6EvgG6427EqyrDR258

FILE NAME: Union Carbide (UC) DATE: 1969 Apr 3 DOC#: UC208 DOCUMENT DESCRIPTION: Internal Report - Asbestos Toxicology Report with Cover Letter Noting Changes in Threshold Limit Value It le u-e i n t c c m a l coxrsssparvsrccs CfvON CA&BIE> C O K P O R A T 5 0 M TefS'ssit? M e s s r s : Oiri'iien a ta tlo n Copy * C. Benjamin T, F. Frangos B. E. Godard J. L. M yers / J. A. Riddle N . J. Setter J. T. Sinclair J. R. Stickney W. S . Young D aft O riginating Dapf, A n iw e rh g lattar data $!>! ' 270 PARK AVENUE. NEW YORK, NEW YORK 10017 A pril 3, 1969 . Medicad Department A sb estos U _U K 1V ED APR 71369 U .C C . CHZM. 6. FtASUCS G entlem en: Both because of changes in regulations and availability of data developed after the issuance o f our report in 1964, Dr. D ernehl and I have rev ised the asbestos memorandum. A copy of the rev isio n is enclosed. The m ajor changes are the d ecrease in the Threshold L im it Value from 5 m illio n particles per cubic foot o f air to 2 p articles per cubic foot of air. (There is a lso a provision for another m ethod of counting but it d o es not app ear applicable to ou r short fib er a s b e s to s ,) We briefly d iscu ss m esoth eliom as, but data is too scanty a s yet for a definite policy to be established. It is worth m en tion in g that th e A m erica n C o n feren ce of G overnm ental Industrial H ygienists considered in 1968 a requirem ent that a irlin e respirators be required for all contact with crocidolite a sb esto s. The r e s o lu tio n did not p a s s , but m a y com e up a g a in in fu tu re m e e tin g s . Any questions or comments w ill be w elcom e. V ery truly yours, KSL:lk E n clo su re . L. * :SBESTOS TOXICOLOGY REPORT It has been known for years that some 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 has been generally accepted that a worker will not develop asbestosis if he is exposed to no more than 5 million particles per cubic foot of air, even if this exposure con tinues for his entire working lifetime. Although no eases of asbestosis are known to have occurred when exposures have been maintained at or below this level, the ACGIH (which sets the threshold limit value (TLV) in the U. S. A.) has indicated they Intend to lower 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 V/alsh-Healy Act placing the TLV for asbestos at 2 fc-ilion 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 A 0 3 3ft 2- beani 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 asbestosis. It is believed by most authorities that these cases have been associated with exposures significantly 0 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 as twenty to forty years earlier. There is considerable evidence that crocidolite 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 operatic ns. They include closed flovf systems, ft 0 3 1 3 rj wet processes where possible, and adequate exhaust ventilation whore openings in the system are necessary. Pelletizing is sometimes used to improve the handling characteristics of otherwise dusty materials. Where satisfactory containment to stay within the Threshold Limit Value is impractical or impossible, efficient and reliable respirators are for the protection of the employee. A program of environmental monitoring is highly desirable to determine that xhreshold Limit Values are not being exceeded. Xn paper manuiacturing, 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 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. Pre-employment and 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 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 &03 u c 4 -4- have to be well In' excess of any levels acceptable to the cons-. :.r~for the asbestos concentrations 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 dusrs encountered in industry, it is as readily controlled as other such dusts and it can be used safely with appropriate precautions. Industrial Medicine And Toxicology Department Union Carbide Corporation i M)3 K