Document YDr3JzYvKLoM8JnRzw4b76eGO

Biochemical Research Laboratory The Dow Chemical Company */DO EXPOSURE TO FINE DUSTS ENCOUNTERED BY WORKERS CUTTING VARIOUS TYPES OF - PIPE COVERING MATERIAL File: Date: By: T2.1-3-1 July 21, 1965 E. J. Schneider Date *7/11rn / (oS Date 7- Z 2-/CS PROBLEM A question was raised by shop personnel after reading an article of the health hazards associated with exposure to asbestos. Is there a health hazard from asbestos in cutting various types of pipe covering material used at Dow Corning? The Environmental Research Laboratory was asked to evaluate the exposures to the fine dusts encountered by workers cutting the pipe covering material and to determine the possible health hazard. CONCLUSIONS 1. Concentrations of total dust in excess of acceptable levels can be encountered by workers cutting pipe covering material both by nand and in using a table saw. 2. A total dust count or the number of particles per million cubic feet of air also exceeds acceptable levels at times. 3. The amount of asbestos fibers of significant length found within the dust exceeds 25 per cent of the fiber content, RESTRICTED: for use within 'The Dow Chemical Company only Biochemical Research Laboratory T2.1-3-1 Page 2 however, fibers constitute only 10 per cent of the total i dust. The possibility that Dow Corning workers are being exposed to excessive amounts of asbestos fibers within the important fiber lengths (20-50 microns) is unlikely, however, it is advisable and prudent to have workers wear respiratory protection while cutting pipe covering material. This is especially true when using a table saw. 4. No one type of pipe covering material was found to have a significantly greater amount of asbestos fibers than the others. The Phillip Carey Plbercel material does produce considerable more fine dust than the others when cut. ASBESTOS In reviewing the literature^ it is learned that the most common form of asbestos, is known as chrysotlle, a hydrous magnesium silicate containing from 12.5 to 14 per cent water of crystallization. There is another form of asbestos derived from amphiboie which occurs as a variety of minerals consisting of iron, calcium and magnesium silicates with little water of con stitution. This latter type of asbestos consists of shorter fibers but is more stable chemically than chrysotlle and more resistant to acids and heat. (1) Industrial Toxicology - L. T. Falrhall, pp. 19-21, 1957 b I UUUUDD^ ST0000570 Blocnemical Research Laboratory T2.1-3-1 Page ? It Is this latter type of asbestos which is thought to be used in the various pipe covering material tested because x-ray diffraction analysis of the materials showed them to con tain tobermorlte, a calcium silicate form of asbestos. The inhalation of asbestos dust produces a condition known as asbestosis. Asbestos is the only silicate apart from talc and mica which does not contain free silica and yet produces pulmonary lung fibrotic changes. The fibrogenic action differs from silica in that the effects are produced only' by long asbestos fibers. Very short fibers appear to have little or no effect. The long fibers apparently block the finer bronchioles of the lungs and produce fibrotic changes as a result of irritation. The literature^ states that in the case of asbestosis unlike silicosis fibrosis does not progress indefinitely after cessation of exposure. It further states that in order to produce asbestosis in workers exposures must be in excess of 3 millions particles^cublc foot for extended periods (greater than 10 years) . and the fibers in the range of 10-250 p in length. Some authorities '' Indicated that only those asbestos fibers in the 20-50 p range are significant for producing asbestosis. The present Industrial Hygiene Standards state that for control the number of particles of a3Destos dust be kept beLow v '-I-n---d---u---s--t--rial Hygiene and Toxicology - Prank A. lattv. Vol. I. pp". jya-399^5g:------------------------- -- Biocnemlcal hesearch Laboratory 72.1-3-1 iage 4 5 mpcf and that for nusiance dusts of any type the number of particles must be below 50 mpcf or 15 mgs total dust per cubic foot Ul` .1 ,. . PRESENTATION UK DATA Kanj .*. i960 a visit was made to Dow Corning to make measurements ^:>c dust exposures encountered by workers cutting pipe covering ...^^.lal. In a small room (approximately 10' x i5') adjacent to u.< i.;i ocnter snop building 409 a worker was asked to hand saw sever 1 <-ces of the various types of pipe covering material used at Dow Corning. Air samples were collected in his breathing zone while sawing the materials. Analyses were made for both total ou.i .-ind the number of particles of dust in the contaminated air In another- ....ail room (approximately 8' x 6') part of tne pipe shop building 316 tests were repeated for two different pipe covering material*, wnile a worker used a table saw to cut tne materials. At botxi . .. ...ons only general ventilation was used with no local exhaust for dust collection. The air samples collected for total du3t lo:io were. nt*:r sent to Dow laboratories for x-ray diffraction analysis a no u.or, microscopic evaluation. Table 1 snows a summary of the results obtained fur' ihe air samples by the various analytical i^chnlqu'V . 1/snnnnK ~ rx ~.*s73 EvrrrrT'-ED SIUUUU5/2 ^ c /r ttv i..otx s various types cp pipe covering materials . Elocnemlcal Research Laboratory T2.L-3-1 Page 6 - The total dust exposure Is not excessive In hand sawing most;-of the types of pipe covering material, however, sawing the Phillip Carey Fibercel material does produce a very fine dust and does produce excessive concentrations of dust. The use of the table saw as would be expected produces very large quantities of dust even for a.not too dusty material such as the Baldwin Ehret Hill Unlbestos. The dust count in millions of particles per cubic foot did exceed in all cases the 5 mpcf Industrial Hygiene Standard for asbestos. However, because asbestos fibers represent approxi mately 10# of the total dust , and because only approximately 2556 of-the-fibers ..are considered of . significant size, it is doubtful that workers encounter a health hazard in their normal work load of cutting pipe covering material. The practice of using a table saw either within a shop building or out in the field should not be continued without adequate control of the dust or the use of respiratory devices. It also seems advisable to encourage workers to wear respiratory protection when hand sawing material. Any Bureau of Standards approved dust respirator should prove adequate to filter out tne asbestos fibers. ST0000573 Biochemical Research Laboratory T2.1-3-1 Page 7 UNIT INDEX Measurements were made of the du3t exposures encountered oy workers .cutting pipe covering material, PiDe Shop Department, Dow Corning Corporation, Midland, Michigan. Concentrations of total duct in excess of acceptable levels can be produced both in hand sawing and in the use of a table saw. The amount of asbestos fibers found did not constitute a health hazard. Respiratory protection is recommended to be worn when cutting pipe covering material. DISTRIBUTION Jack Quinn, Safety Department, Dow Corning Corporation H. H. Gay, M.D., Medical Department, 607 Building A. W. Wilson, Safety Department, 401 Building C. Middleton, Safety Department, Ludington Division W. Snodgrass, Maint. Service Admin., 49 Building (7/9/71) (4) b lU U U U S /4 TO. E. J. Schneider THE DOW CHEMICAL COMPANY ANALYTICAL LABORATORIES REPORT DATE 20 Kay 1965 OUK( . 700-^00-003 A L """in _ ^ * Tout MUMtca OltCflFTCW S 57-9^5 FtOCLLM HYDRATED CALCIUM MILICATE ON LATEX FILTERS MICROSCOPY Particle clze determination About 65>% About 90% 0 < 10 u < 20 u > 50 u Filters 1.5, 6, 6 About 8556 About 95?6 < 10 .. < 20 Filters 2, 3. ^, 7 About 1*5% About 9056 < 10 u < 20 u Fiber size determination About 1% About 10 % About 65% < 10 u < 20 u > 50 u Filters 7 About 1% About 25S About 90 % < 10 u < 20 u > 50 u ? i li;<crs 2,^,6 About 556 At cut 10 % About ^5% < 10 U < 20 U > 750 u Filters 1.3.5.S About 156 About 6% About 70 56 < 10 u < 20 u > 50 u Fibers would account for about 10 <% of the residue n.i. it 8 ". R Lape bb 12 bit. 20 U<XCD ____ *Otf HI- J- iVA\. P. A. Traylor 2351 W.00. 57*4 PHOTOMICROGRAPHY ALS 57 -w________ Photomicrographs were prepared employing Bright field v Phase Contrast Oblique Transmitted Light Dark field Polarized Light Oblique Reflected Light__ ____________________________________ ______________________________________________ technique to show __________particles an~i Hbers Label Data for 8 x 10 prints contact prints Negative # L5-525 L5-526 Sample Latex Filter if 2 Latex Filter // 8 r Microscopy B. F. B. F. Magnlf. 300X 300X ( < ( < THK OOW CHEMICAL COMPANY 168499 CHEMICAL PHYSICS RESEARCH LABORATORY TO ' ihIjoiG M'M**t* E. J. Schneider lUBiCCY . Biochem Res. Lab. 1701 X-ray Diffraction Analysis of dust samples from cutting pipe covering at Dow Corning Charge mo. 1219-26 OAIC RECEIVED _ 2-2-65 ! utco . H. *V. Rinn OAfl 2-11-65 . #1 C.0001 g) Tobermorite - XCa.0*Si02 yH20 where x varies between 0.8 and 1.5 and y between 0.5 and 2.0 *2 (>.0001 g) Same as #1 #3 (.0004 g) Same as #1 *4 (.0020 g) Same as n1 #5 (.0008 g) This sample gave a very weak pattern of hydromagnesite - SHgCOj-MgOH)2-3H20. There could be amorphous material present. #6 (<.0001 g) Tobermorite and some calcite. Pattern quite weak, probably because of small sample. #7 (.0052 g) Mainly tobermorite with 10-20% tialcite - CaCOj. #8 (.0036 g) Mainly tobermorite with 5-10% calcite. No quartz was detected in any of the samples. Note on appearance of tobermorite - from Crystallographic Data for the Calcium Silicates by Heller and Taylor. Natural mineral from Ballycraigy: minute, radiating agregates of fibers with distinctive silky lustre on the cleavage faces. Natural mineral from Mull or Skye: fine geared aggregates of minute, birefringent crystals. Synthetic material: minute irregular crystals, birefringent. HWR:abj 2-11-65 3 *vitt(t i M i. i. m ffSOOOOlS ' -S ^ o o o o j.9 b I U U U tib d U I ( ( I ( c ( t Table- T "Xr'VUJRE TO TIME DUTT". T-'.i.'TO TITERED BY V/ORXErU Industrial Hvrienc "Undan, Cuioar.co 'c Industrial Hygiene f.tandaro, Asbestos ;-'l'r. f'oeration (Total Dust Kxnosure) mr/m ' fDust Frunt) * `. 0 . F. /-'lav Diffract: Breathing zone of worker hand sawing Baldwin Ehret Hill calcium silicate curved block 2M thick Repeat same material 0.4D o .09 A vg. 3.2 rS. 4 4.8 44.6 12.6 14.5 Tobermorite (0.9-1.5) Cao . Tir. Tobermorite (O.0-I.5) Can . Dir,, Hand cawing Owens-Corning Kaylo flat block 2" thick Hand 3awing Phillip Carey Flbercel curved block 2" thick 3.60 A vg. 17.90 A vg. 17.3 22.2 19*'3 7.9 12.1 10.0 Tobermorite (0.8-1.5) CaO . r.i`r -- Tobermorite ,(0.8-1.5) CaO . oiO? Hand sawing Phillip Carey 855S MAG curved block 2" thick 7.20 11.0 3MgC03 . MgCH)2 . 7H Hand 3awing Baldwin Ehret Hill Unibestos flat block 2" thick U.O'J Id.5 Tobermorite (0.8-1.5) CaO . E102 Breathing zone of worker u3ing table saw to cut Owens-Corning Kaylo flat block 2" thick Using table saw to cut Baldwin Ehret Hill Unibestos flat block 2" thick =~-- ------------- 55! 77.90 53-90 -- 59.n Tobermorite (0.8-1.5) CaO . DU - t Tobermorite (0.8-1.5) CaO . SiO,, i F ^o o o o ^ IG VA:,Ir.'J." . Y lusts .... fibers . . . rlrsv G.'-'/EKIN'G WTEHIAi 15 mr/m * 5 M.F.C.F. :tion Ana i".; La Klectron Microscope Analysis) Particle Size (Fibers 10* of Tr tal Dust) Fiber Size 1 20-50 p 10, . (0.5-2. .) H,0 %5% 9556 <10 p <20 p 156 <10 u 556 <20 p 7056 >50 p 2556 45* 10, . (0.5-2.0) H,0 9056 <10 p <20 p 5% <10 p 10% <20 p 45* >50 u 4556 | 2 10, . (0.5-2.0) H,0 '*555 9056 <10 p <20 u 156 5* 70% <10 p <20 p >50 p 2556 C? ` 10, . (0.5-2.0) H,0 9056 <10 p <20 p ju ' 2' ' 3H20 8556 <10 p 9556 <20 u 0, (15* <10 p ilO, . (0.5-2.0) H,0 95* <20 p .r. 45$ <10 p 310, . (0.5-2.0) 11,0 90 <20 u r\ * >10, . (0.5-2.0) H,0 85* 95* <10 p <20 u 5* 1056 45* 1* 5* 70* 5* 10* 45* If, 256 90$ 195 5* 70* <10 p <20 p >50 p <10 p <20 p >50 u <10 p <20 p >50 p <10 p <20 p >50 u <10 p <20 p >50 p 45* 2556 4556 a* 2556 INDUSTRIAL HYGIENE SAMPLE RECORD UtTLMC MCTMOO MTU tATI fNka BLOC. OATI i TltffMCMtaUM T*>i~ 3- f BOTamBTEI Ot 0B1FICB MO. BB0CB11 t/n/Lr i Dcu jhps MTOMTItUTTMC ^ OUTHM Tar. IMUM TUT. MAMMAL Arnerr*s. v<mtr.atv5T _____ W '*/r --------------- t' r" Oe^O/fc SArtE BOTTLE ^4^. fief descbiptioh iTAir TIME IW COHCEMTBATIO. 2/3/ -/ 'h-Cti*1 BZ UJ^-v. -- CX^T/*JU> Cl< SX^t. C--L /o-- 2/ 3 / -2 S*___ ^ZCJl . r-- 2/3/ -3 *^6.^3 -D-2--------- ^0 v>e*- Ko<^?Cr l"/Ur jT sUni. I 2/3/ -* B2-bmLrnm* . . /^A/Zy Gw*. JU~cti 2'r^r^-x--i-. <? /L^*-L---c-r--- r--. *0/ -r D2 1+---J-><-*-% ^. *Z'--^G^v>k. 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