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O F* _rV IVI E RI G A, I IS" G. 201 KING MANOR DRIVE. KING OF PRUSSIA. PA 19406 1215)277-3900 April 20, 1979 MTj. X. H. Weaver Coroorate Director Envir. RAY3EST0S->LiNHATTAN 123 E. Stiegel St. Manheim PA 17545 Control Dear Ike: PLAINTIFF'S EXHIBIT I thought you would be interested in the enclosed report from Dr. Arthur Rohl of Mt. Sinai Hospital Medical Center. We have been anxiously awaiting the results of Dr. Kohl's tests and needless to say, are very pleased with the report and what he has to say about NIXFISK'S ASBESTO-CXENE systems. Sincerely, NILFISK OF AMERICA, INC. PRobert S. Magc^lain ! President RSM:ds Enclosure i* MAR 000546  r wH.wr* April 11 1979 r Mr. Robert S. Magdelain, President Nilfisk of America, Inc. 201 King Manor Drive King of Prussia, Pennsylvania 194C6 . .. Dear Mr. Magdelain: This will report the results of air sampling tests conducted, in October 1978, to determine chrysotile asbestos concentrations dur ing brake repair work. Our major objective was to determine the efficiency of the Kilfisk Asbestos System utilizing HEPA filters, particularly with regard to submicroscopic asbestos fibers. Studies conducted in our Laboratory and elsewhere have demonstrated that free asbestos fibers present In brake drum dusts are predominantly shorter than Sum in length. In. particular,, it was found that about 75Z of the fibers in such dusts were less than 0.3ymin length, as determined by transmission electron microscopy. Thus, the optical microscopic technique used by OSHA for determining asbestos levels In workplaces (in which only fibers Sum or longer are counted) would overlook a large number of asbestos fibers in air samples. That is, the total asbestos exposure in terms of fiber number, mass and surface area would be significantly greater than the levels determined using the OSHA fiber-counting method. Therefore, it was of considerable Interest to us to have an oppor tunity to test the efficiency of the Nilfisk Asbesto-Clene System. To do this personal air sampling was carried out on the exhaust of a HEPA-filtered vacuum dust collector and, simultaneously, on a garage mechanic cleaning a brake drum with the Nilfisk brake en capsulation cylinder. Three such tests were made. Background air samples, also using personal air pumps, were taken. Tor each of the tests, a sample of settled dust was taken from the brake drum. The dusts were analyzed by x-ray diffraction in the stepscan mode to quantitatively determine asbestos contents, using a technique previously published. Asbestos was found in all three samples, ranging from 2.5Z to 4.5Z by weight. The membrane filters were analyzed by both transmission electron microscopy- (X25.000) and by the standard OSFA fiber-counting technique, employing phase contrast optical microscopy. The results are as follows: MAR 000547 Mr. Robert S. Magdelainj President Page 2 April 10, 1979 Sarrole Description Hanograns/cu mater Fibers /tsillili ter (electron microsooov)' (cotical microsconv) N--1 N--2 ' N-3 TEST 1 Background (70 feet from operator) Operator (breathing zone -- 6 ft. from dust collector) Bust collector (EEPA-filtered vacuum) 0 0 oo .? 0 0 0 N-4 N-5 N-6 TEST v2 Background (70 feet from operator) Dust collector (HEPA-flitered vacuum) Operator (breathing zone -- 6 ft. from dust collector) 615 0 59,000 0.12 0 0.5 N-4 V<-7 N-8 TEST S3 Background (same as in Test "2) Operator (breathing zone -- 6 ft. from dust collector) Bust collector (HEPA-filtered vacuum) 615 0 0 0.12 0 0 MAR 000548 Mr. Robert S. Kagdelain, President Page 3 April 10, 1979 Remarks and Conclusions: The tests demonstrate that asbestos levels are virtually eliminated by the use of a system employing brake encapsulation device connected to a HEPA-filterad vacuum dust collector. Without the use of such equipment, fiber concentrations during compressed air jet-bloving of brake drums ranged from 6.6 to 29.3 fibers/milliliter. However, when the Asbesto-Clene System was used, fiber concentrations on both the mechanic and dust collector exhaust were not detected, as verified by transmission electron microscopy. An important exception to this is observed in Test $2, the sample taken on the operator. Prior to this test, this mechanic had worked on brake jobs vichout using the Asbesto--Clene System and without changing his work clothes. This exposure had resulted in contamination of his clothes, re flected in the high residual asbestos concentration of 59,000" nanograms/cubic meter and 0.5 fibers/milliliter. In contrast, the operator in Test ?1 and Test -?3 wore clean coveralls. This points up the need to adhere to the OSSA regulations concerning special clothing, change rooms, etc. to minimize contamination. The background asbestos measurements, of 400 and 615 nanograms/ cubic meter, are consistent with other background measurements taken during brake repair work. They are the result of residual contami nation of the -garage by asbestos. This study has been unique and fortunate in two respects; first because of the great interest and importance of determining chrysotile asbestos levels in such ciretnastances. The data indicate that the Asbesto-Clene System represents an outstanding advancement in industrial hygiene procedures to control asbestos exposure. It has also been a pleasure to work with you in preparing and conducting these tests. If there are any questions regarding the results or conclusions in this report, please do not hesitate to contact me. ANR: jta Arthur N. Rohl, Ph.D. Environmental Sciences Laboratory MAR 000549