Document wD4NGwnn4E3Y4eJvYqL3vd4yJ

FILE NAME: &'ZZ&' DATE: D DOC#: &' DOCUMENT DESCRIPTION:ZZ:ZZ^ZZ& ZZ John H. Field Dept. 1501 - Bldg. 276-B John W. Born Dept. 0020 - Bldg. 5-H Surveys of Asbestos Fiber Concentrations in Building 276-B : NTIAL 3/2/73 Summar_ On December 18 and 2s, 1972, I measured atmospheric concentrations of asbestos fibers in Bldg. 276-8. The measurements occurred during each customary cyclic operatiiiii:-The basic operations were loading, bandtrucking, and unloading the bags of asbestos and then emptying the bags into the churns. The Occupational Safety and Health Act (OSHA) has set concentration limits of 5 fibers (longer than 5 micrometers) par milliliter until July 1, 1976. and 2 fibers/ml thereafter. The majority of operations involving asbestos in Bldg. 2764 are in serious violation of the OSHA limit. Prompt engineering and administrative steps must be taken to correct the hazardous conditions. Recommendations 1. Install a local exhaust ventilation system at each chute through utich asbestos fibers enter the churns: a. Fit each local exhaust system with a disposable filter. b. Dispose of the filters regularly in an approved manner. c. Gave Dept. 0020 remeasure the atmospheric concentrations of asbestos as soon Al the exhaust systems are installed. 2. Use a portable vacuum cleaner to remove residual amounts and spills of asbestos fibers promptly: a. Make sure that the vacuum cleaner has a bag or filter which is approved for collecting asbestos fibers. b. Dispose of the filters regularly in an approved manner. c. Make the vacuum cleaner permanently available in the churn and storage areas. d. Have the compounder remove the asbestos fibers from the churn and floor surfaces and from his clothing end person as soon as the batch is mixed. e. Have the supply man remove the asbestos fibers from his clothing and person and from the hand-truck as soon es the bags have been delivered. A 000350 -2- f. Have the supply man remove the albeits fibers from the floor, skid, and beg surfaces in the asbestos store's areas Whenever necessary. 3. Obtain and use a waste container for empty asbestos bags which viii 111141.1.136 the dispersal of fibers during the disposal of the bags. 4. Reseal the open bags of dried asbestos before removing them from the hot room. 5. Until the local exhaust systems and the vacuum cleaner are in satisfactory regular use: a. Have all workers 160 art exposed to asbestos fibers wear dust respirators shich are approved by the U. S. Bureau of Mines for asbestos fibers. b. Have all such workers remove the asbestos fibers carefully from their clothing and persons promptly to avoid breathing or swallowing the fibers afterward. c. Have all such 'workers remove the asbestos fibers from the work surfaces as soon as the operation is finished. 6. Notify Dept. 0020 when the local exhaust systems and the portable vacuum cleaner are first put into use. 7. Notify Dept. 0020 whenever there is a new job classification Which requires exposure to asbestos fibers. Results and Discussion; The surveys of the operations in Building 276-B indicate that the present excessive asbestos concentrations are correctable. However, it appears that extensive engineering improvements are necessary. Measurements of ateospheric concentrations of asbestos fibers were made during complete work cycles. These cycles are summarized in the accompanying table. There were two basic types of work. Ow type involved loading the asbestos bags fromathe supply area onto a hand tuck, taking the bags to the Churn area, and unloading and restacking the bags. The second type involved emptying the asbestos from the bags into the Churns through the chutes. There are two types of churn chutes. Oue type has a hood over its waist-high opening. The other type has a hinged lid pt its opening about IS inabes Above the floor. The asbestos fibers mere used both in the as-received condition snd after being dried in a bot room. The table states the atmospheric concentrations of asbestos fibers during the various types of wotk. Those concentrations were measured in the breathing zones of the workers. The workers included the supply man wb,0 delivered the bags to the churn area and the compounder Who A 0003F.1 -3- fed the asbestos into the churn. In two of the four cases the same man did both jobs. The table gives the exposure times for the several types of work. It than gives the corresponding asbestos concentration in the air. The four concentratiorui must be conparad with the threshold limit value (TLV). This value is the 8-hour time-weighted limit for the average atmospheric concentration of asbestos fibers longer than five micrometers. At present this limit is five fibers per milliliter (ml). As of July 1, 1976, the limit will become two fibers per ml. In both cases concentrations from 5 to 10 fibers per ml are permitted for 15 minute periods each hour up to five times daily. The time-weighted average concentration still must not exceed the threshold limit value. Studies of the information in the accompanying table permit several conclusions. each average asbestos concentration plE single cycle exceeded the threshold limit value. The TLV is a time-weighted value which is averaged over an 8-hour workday. Whether the measured concentration actually exceeds the TLV depends upon the nature and number of the cycles of exposure per day. However, in all four operations the concentration exceeded even the short-ties limit. Therefore, in each case the exposure to asbestos fibers wets in violation of the OSHA standard. Loadingi transporting, and unloading the bags of asbestos expose a worker to a higher concentration of asbestos fibers than does emptying the seas number of bags into a churn. The atmospheric concentration during the addition of asbestos to the churns was higher for Churn 313 than for Churn 108. The higher value in the Cele of Churn 313 may be due to two features. First, the opening of its chute is closer to the worker's breathing sone. Second, the Shape of the chute tends to direct the escaping fibers toward the worker's face. Furthermore, the asbestos fibers blew out of both chutes after addition of the asbestos when the mixing started. These clouds of asbestos fibers undoubtedly added significantly to the average concentrations. One likely cause of the higher exposure to the supply man is the dust collection on the stacks of non-dried asbestos begs. Some asbestos escapes from the bags during stacking. When the bags are Worn off the stacks and put on the hand truck and then onto -the floor, this dust rises into the worker's breathing sone. removal of the dust with the vacuum cleaner before handling sould minimise this source of exposure. Also, prior to drying the asbestos in the hot roam, the supply men cuts off the tops of the bags. These openings allow the asbestos fibers to rise into his breathing sone when the bags are placed on the band truck. Resealing the bags after drying mould eliminate this source of exposure to asbestos fibers. Until July 1, 1976, the required local eihaust ventilation system must capture all but five fiber* per ml of asbestos in the air around each chute. After that date it must capture all but two fibers per ml. This capture might be accomplished by either one exhaust duct on each of two sides of the chute or a full exhaust ring. In addition to the A (200.7::52 local elhaust system some method of preventing blow-back of the asbestos through the chute will be necessary. In the case of the chute with a hinged lid, a gasket seal and tight closure nay be sufficient. Also the local exhaust system oust avoid the release of hazardous concentrations of asbestos fibers to the atmosphere outside the plant. The local exhaust system therefore may require a filter. A disposable type of filter is recommended. The workers must either clean or dispose of the filters regularly in an approved manner. Another source of exposure is a dispersal of asbestos fibers into the air during the sweeping after adding the esbestos to the churn. Therefore, I recommend the use of a vacuum cleaner to remove residual amounts and spills of asbestos fibers promptly. The vacuum cleaner most have a filter with the right pore size to retain asbestos fibers longer than five micrometers. The filters must permit safe and easy disposal. Use of the vacuum cleaner should sake little or ao sweeping necessary. Since both the supply nen and the churn operators must use the vacuum cleaner at widely separated location, it must be portable and readily available. It is important to remove the asbestos fibers from each worker's cloth- ing and person as SWISS he has finished handling the asbestos. This removal also can best be done with the vacuum cleaner. Asbestos fibers from ''empty" begs are a potential hazard during disposal. A different type of waste control for the empty bags is necessary to minimise the dispersal of the asbestos fibers during the disposal. It is obvious from the accompenyeng tale that the workers who are exposed to asbestos must have temporary respiratory protection. They will be required to wear dust respirators. Which are approved by the U. S. Bureau of Minas throughout such exposures. These workers also most remove the asbestos fibers from their clothing and persons promptly to avoid breathing or swallowing the fibers afterwards. OSHA requires two safeguards for workers exposed to asbestos fibers. It requires a comprehensive annual pulmonary examination for each worker exposed to asbestos fibers. It also requires measurements of the atmospheric concentrations of asbestos fibers Logger than five micrometers in each area Where asbestos is used. Department 0020 therefore would appreciate prompt notice of any new asbestos process and any new job classification involving such asbestos exposures. tan cc: John R. Cadres Kenneth G. Kamp AO/141' 7/. bn V. Born A 00053 -5- Asbestos Exposures During the Compounding and nixing of Adhesives Description of Work during Atmospheric Sampling Emptying of fifteen 50-lb. bags of Code 164 asbestos (non-dried) into Churn No. 108 Transporting of fifteen 50-lb. bags of non-dried Code 164 asbestos to the Churn 108 storage space Transporting of twenty-six 50-lb. bags of dried Code 164 asbestos to Churn 108 and emptying of the asbestos into the churn Transporting of fifteen 50-1b. bags of non-dried Coda 164 asbestos to Churn 313 and emptying of the asbestos into the bhurn Exposure Time (min.) 8.5 3.0 25.5 12.5 Avg. Asbestos Concentration* (fibers/ml) 11. 24. 7.4 24. * The present 8-bour time-weighted limit (TLV) for the average atmospheric concentration of asbestos fibers longer than 5 micrometers is 5 fibers per .ml. As of July 1, 1976, the limit will become 2 fibers per ml. In both cases the concentration must never exceed the ceiling limit value of 10 fibers per ml. A 000354