Document gEJK3VkqXDbv0w9qEyowMJ9xe

FILE NAME: Longview Fibre (LF) DATE: 0000 DOC#: LF010 DOCUMENT DESCRIPTION: Unpublished Internal Report from Union Carbide UNION CARBIDE CORPORATION 270 PARK AVENUE. NEW YORK. N. Y. 10017 ASBESTOS TOXICOLOGY REPORT In has been known for many years that some persons working in asbestos production ware prona to develop a disabling lung disease. In time, this condition became known as asbestosis and was related to ex posure 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 generally accepted that a man can work a 40-hour week for a life time without developing asbestosis if the as!. :stos 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 aver age lighting conditions. - , Several years ago, it was reported that there wa.3 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 characteristics of otherwise dusty materials. Where satisfactory con tainment 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 7000 6869* 169*008 QVSN2d IBI HP UCASB00086964 - 2- 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 examinations 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 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 Toxicology AQ7006 UCASB00086965