Document O1LwjYB89a2j1Y60b7jrzEBYe

September 13, 1967 Dr. Levis J. Cralley Director, Epidemiology and Field Studies national Center for Urban and Industrial Health Public Health Servloe .lOlii Broadway Cincinnati, Ohio U5202 > /. .^v^' Dear Dr. Cralleyi SUBJECTi U.S.P.H.S. Environmental Survey for Asbestos at Pittsburgh Coming Tyler, Texas and Port Allegany Plants I am still awaiting oopies of the reports on the subjeot plant surveys. lour assistance in this matter will be appreciated..*v.V For your information, X have enclosed a copy of a report of a survey done at Tyler by J. T. Destefano, our Class Division's Industrial Hygiene Engineer. Sincerely, lnr cci Hr. J. Vf. McMillan Mr. L. 0. Griffith .iV* Lea B. Oraat, H.D. " - 1; 4 ** V v? "v -i ^ INDUSTRIAL HYGIENE SURVEY PITTSBURGH-CORNINS, TYLER, TEXAS At the request of Lee B. Grant, M.D., a dust survey was made of the Tyler plant on November 29, and 30, 1966. The purpose of this survey was to re-evaluate the plant in terms of any significant changes in levels of airborne dust since the last survey of August, 1963, by the Industrial Hygiene Foundation In evaluating a dust exposure, the threshold limit values as promulgated by the American Conference of Governmental Industrial Hygienists are used as guidelines^ They represent levels of dustiness which should not be exceeded on a timeweighted average basis for an eight hour day for a man's useful working life. The threshold limit value for asbestos dust is 6 million particles per cubic foot of air (mppcf). Before discussing the results it would be well to explain some of the changes that have taken place in recent years with regard to dust counting techniques. Most of the threshold limit values for dust (particularly silica dust) were developed in the 1930's in the granite sheds of Vermont. In those studies, the counting technique called for light-field illumination at 10QX magnification Since that time, however, better optics, giving better resolution at higher magnification have become more common. Therefore, the desire to use the more sophisticated optical systems of today must be balanced against the excellent correlation with medical findings that the Vermont granite studies produced. This is perhaps, an over-simplification of the situation, but the point being made is that one of the better optical systems was used for evaluation o' the samples from the current study. It is believed that this is the reason for the dust counts reported herein being approximately ten times greater than previous studies of the same plant. In addition to total dust counts, however, this study also presents fibrous dust counts. It can be seen that these fib rous dust counts are of the same order of magnitude as previous studies. The reason being that a fiber, which is defined as a particle with a length at least three times greater than its width, is large enough to be seen at the old 10GX magnification as well as the more sophisticated systems. The results of the study are shown in Table 1. A comparison of the fibrous dust counts with the threshold limit value of 5 mppcf indicates that seven of the sixteen values exceed this limit. It is felt that the values reported herein are representative of conditions in the plant at the time of the visit, and the following recommendations are being made from the test results as well <s personal observations! 1. Better ventilation, or a better materials handling system, or a combination of both, is needed on the feeders. . 2. Constant inspection and immediate correction of any air leaks in the equipment is needed as is indicated by a dust count of 20 mppcf in the general area of No. 2 mill. 3. Better ventilation is needed in the sawing area. An evalua tion of the present system by means of suitable air velocity measuring equipment would be a logical first step.4 4. The use of sand on the floor as a lubricant for the movement of cardboard boxes should be discontinued. The addition of a silica hazard to an asbestos problem is'unwarranted. 'O 2 5. The air cleaners should not be located Inside the building. Positive pressure bag collectors of this sort may be inexpen sive, but undetected leaks can put a significant amount of dust back into the air. Furthermore, re-circulation of exhausted air is poor practice, in addition to being illegal in some states, because it assumes a collection efficiency approaching lOOfc which is rarely true, especially in older installations. The proper type of dust collector would eliminate the excessive dust concentrations from shaking the dust bags. JTD/jcw 9/11/67 J. T. Deste/ano Safety &. Industrial Hygiene Engineer / i TABLE 1 Process Area 1. *BZ Scrap Crusher Operator 2. B2 Feeder Operators 3. No. 2 Mill ~ General Area 4. Production Floor - between Nos. 1 and 2 10. BZ Feeder Operator 11., No. 3 Mill - General Area 15. BZ Scrap Crusher Feeder 16. Production Floor - between Nos. 2 and 3 Total Dust ffiPDCf 34.7 3B.8 77.5 12.5 45.0 2.5 56.3 10.0 Sawing Area 5. BZ Butt End Catcher - big end cut & rip saw 43.2 6. BZ Tie Machine Operator - packing (inspection also) 10.0 , 7. BZ Block Band Saw 53.0 * 8. Saw Room-Inspection Station & Tying 9. BZ Butt End Catcher - big saws 13. BZ Saw Operators - both block saws operating 14. BZ Saw Feeder - big saws 26.2 7.5 30.0 15.0 Miscellaneous 12. BZ Operator shaking dust bags 17.5 Fiber Dust mppcf 3.8 . 6.3 20.0 2.5 20.2 1.3 0 2.5 15.0 2.5 10.5 2.5 0 7.5 2.5 32.6 BZ - Breathing Zone JTD/jcw 9/13/67 1. i L x | I f t i V } k i' iV 1' t i. '} *i . ' . i 'i <v i (