Document jgy5yKrXqrrMXw8BQdjb6B3g2

E. I. du Pont de Nemours & Company Wilmington. Delaware EMPLOYEE RELATIONS DEPARTMENT PLAINTIFF'S EXHIBIT DUP-1385 w/ KERR 7 (Y.K.) LTD DETERMINATION OF AS3EST0S IN TALC Ref:- Letter of L. Appleby to D. J. Kerr July 11, 1373 You recently requested comments on the adequacy of determining asbestos in talc by the current optical microscope method and the advisability of converting to use of a scanning electron microscope or an x-ray diffraction apparatus for this analysis, we have studied this problem and our conclusion is that it would be premature at this time to change to another method. The information provided by the Barrot article on the deficiencies of the phase contrast microscope method is not new. In May, 1977 the Analytical Chemistry Division of the (U.S.) National 3ureau of Standards listed a number of objections to the phase contrast microscopic technique in a project carried out for the Occupational Safety and Health Administration (excerpt attached). Some talc producers have also questioned the method. The procedure is not very precise (+ 70? for 95? confidence limits), it is subjective in nature and its ability to differentiate between asbestos and other fibers has been questioned. However, the current U.S. Government Regulations still require the optical method of analysis for workplace air sampling. The National Institute for Occupational Safety and Health issued a "Revised Recommended Asbestos Standard" in December, 1976. This publication surveyed the state of the art (scanning electron micro scope, x-ray, differential thermal analysis, etc.) and concluded, ". . . phase contrast microscopy is the only generally available aA nd.4 practical analytical technique ae\ +t lthUea preseaanIt- ^timmea D Dw 'Iloss, THERE'S A WORLD OF THINGS WE ARE DOING SOMETHING ABOUT DU 054945 D. J. Kerr August 24, 1973 Page Two "Application of [electron microscope] techniques to routine samples is rot practical because of extremely high analysis costs ($200 - $400/sample), long analysis times and limited equipment availability." we also call your attention to the conclusions reached by the TJ.K. Health and Safety Commission's Advisory Committee on Asbestos (article enclosed). They concluded that the current optical method should be retained because alternative techniques are not yet developed to the point at which they could be put into reliable everyday use. In addition, the new techniques have not been correlated to the data generated to date on exposure and disease development or TLVs. This commission did call for an expansion of research to develop new and existing techniques for monitoring asbestos. There is no work underway at present in Du Pont U.S.A. to develop a better method for determining asbestos in minerals. However, we are maintaining a surveillance of the developments in the field and we will advise you if a change in procedures is recommended. SAFETY AND FIRE PROTECTION DIVISION V, dl, W. C. Haaf, Occupational Health Engineer Engineering Section JRM:pch Attachments - 2 0UP 1110952 DU 054946 A REPORT ON THE FIBER CONTENT OF EIGHTY INDUSTRIAL TALC SAMPLES OBTAINED FROM, AND USING THE PROCEDURES OF, THE OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION Prepared lor Occupational Safety and Health Administration Department of Labor Washington, D. C. 20212 Prepared by the Staff of the Analytical Chemistry Division, P. D. LaFleur, Chief Institute for Materials Research National Bureau of Standards Washington, D. C. 20234 May 1977 U.S. DEPARTMENT OF COMMERCE, Juanita M, Kreps, Secretary Dr. Betsy Ancker-Johnson, Assistant Sacratsry for Sciatica and Technology - NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director DU 054947 I. INTRODUCTION A. Purpose of Study This report has been prepared in response to a request received by Dr. John D. Hoffman, Director of the Institute for Materials Research of the National Bureau of Standards (NBS), in a letter dated September 1, 1976 ,'from Djr. Morton Corn, Assistant Secretary of Labor, ^Occupational Safety and Health Administration (OSHA). in that letter, Dr. Corn stated that analysis cf talc samples for their asbestos content was being performed by OSHA and the National Institute of Occupational Safety and Health (NIOSH) but that the methodology was being challenged by some of those regulated by OSHA. Dr. Corn indicated that his request to NBS was composed of two tasks: (1) to resolve the varj.abd.lity in the definition of asbestos fibers in talc, and (2) to determine the asbestos content of some 80 talc samples to be provided by OSHA. Copies of the letter containing this request and the subsequent correspondence between Drs. Hoffman and Corn which provide further background information, are included in this report as Appendix I. It was agreed by both parties that the first of these tasks, i.e., resolving the variability of the definition of asbestos fibers, would be a complex, long-term program which would require input from a number of sources both in the private and public sectors. In view of this, it was agreed that the more limited task, that of determining the asbestos content of the OSHA talc samples, would be addressed by NBS first. As Dr. Corn pointed out in his letter of October 8, 1976, this was recognized not to be a research task but would involve an analysis performed according to the procedures given in 29 CFR 1910.1001. 1 DU 054948 29 CFR 1910.1001 [39 FR 23302, June 27, 1974, as amended in 41 FR 11505, March 19, 1976] deals exclusively with airborne asbestos and does not describe procedures for, nor make any reference to asbestos in talc. It does, however, include the following two paragraphs which are pertinent to the work discussed in this report: "(a) Definitions. For the purpose of this section, (1) 'Asbestos' includes chrysotile, amosite, crocidolite, tremolite, anthophyllite, and actinolite. (2) 'Asbestos fibers' means asbestos fibers longer than 5 micrometers. "(e) Method of measurement. All determinations of airborne concentrations of asbestos fibers shall be made by the membrane filter method at 400-450 X (magnification) (4 millimeter objective) with phase contrast illumination." These regulations do not, however, describe a measurement prooedure but rather prescribe a method of measurement {viz., phase contrast microscopy). A prooedure contains a detailed listing of the sampling of the material, the specific experimental steps to be performed during an analysis, and, often, descriptions of the mathematical calculations to be performed and of the format for reporting results and their associated errors. A method of measurement is defined by a very general statement of the type of measurement to be made, from which a specific prooedure is developed. Since 29 CFR 1910.1001 stipulates only that the method of phase contrast microscopy is to be used for the determina tion of asbestos, NBS requested a detailed procedure from OSHA. In response, NBS was provided with a copy of the OSHA document "Asbestos Fiber in Air" - Method No. PCAM 239, 2 DUP til 0955 I1 1 1 issued March 30 , 1976. h'BS was also informed chat the determination of asbestos, including asbestos in talc, was 1 performed at the OSHA Salt Lake City, Utah, laboratory (OSHA-SLC) , using P5CAM 239. Method No. P6CAM 239, however, 1 deals only with the determination of asbestos in air using phase contrast microscopy to examine membrane filters. 1 Since the determination of asbestos in talc is not described in the document, NBS was told to contact Mr. Willara C. Dixon 1 at OSHA-SLC to obtain an exact description of the procedure used on talc samples. To become familiar with the asbestos in talc procedure, 1 an NBS scientist then visited the OSHA-SLC laboratory and obtained verbal and written descriptions of the procedure 1 used. He spent approximately one and one-half days at the laboratory observing the procedures and techniques used and 1 discussing them with the OSHA employees. At the conclusion of the visit he wrote a detailed report of what he had observed. This report was submitted to Mr. Dixon for comment. A copy \ of the report is included as Appendix II to this document. The portions of the report that are enclosed in boxes are 1 the comments added by OSHA-SLC personnel. NBS scientists also discussed the analysis of talc with 1 a number of other persons. Those contacted are listed in Appendix III to this report. 1 Prior to commencing the actual analysis of the 80 talc samples, we were assured by OSHA personnel that 29 CFR 1 1910.1001, P8CAM 239 and the annotated NBS trip report were the only documents appropriate for documenting the analytical procedure to be employed, and that the process followed by 1 NBS in developing the detailed procedure was proper. I I DUP 1110956 DU 054950 The detailed procedure followed at NBS is given in Section II of this report; however, a brief description of the procedure, and some comments, are given below: Phase contract microscopy, with a mounting medium having an index of refraction of 1.546, is used. Both fibers (a fiber being defined as having a minimum length of S urn, a maximum diameter of 5 pm, and a minimum length to diameter ratio of 3:1) and other particles are counted. Early in the study we determined that the identifi cation of "asbestos" with the procedure used was extremely difficult for the following reasons: (1) Since phase contrast microscopy is only a contrast mechanism, it does not indicate the degree of difference between the refractive index of the liquid and a particle or fiber. For example, if a specimen is mounted in a liquid which matches a refractive index of chrysotile, then the particles and fibers counted would include all fibers which do not have that particular refractive index, e.g., talc, anthophyllite, wollastonite, fiber glass, etc. The same would be true for any other liquid used. (2) Most mineral species have three refractive indices, therefore, any mineral fiber not lying in the correct orientation for the selected liquid will not match and would be visible and would be counted. (3) The amphiboles are end members in solid solution. As a result there may be a large range of refractive indices from one end member to another. One example of such a series would be the tremolite-actinolite solid solution. 4 DUP 1110957 (4) In addition, the most common methods of talc formation are the hydrothermal alteration of ultrabasic rocks such as serpentine and tremolite and the thermal metamorphism of siliceous dolomites. Therefore, during the formation of talc in contact with other minerals, there may be extensive interconversions between talc , and the minerals serpentine, tremolite and anthophyllite. vThese interconversions may give rise to single particles which have a combination of the talc, anthophyllite, and serpentine mineral phases.* (5) There are many materials which may be present in talc which have overlapping refractive indices, Mineral Wollastonite Tremolite Quartz Talc Chrysotile Refractive Index 1.63 1.S99 - 1.637 1.55 1.539 - 1.589 1.493 - 1.567 (6) Even if the refractive indices were known, positive identification of minerals could not be made since there may be interferences from other materials. * Deer, W. A., Howie, R. A., and Zaussman, J., Rook Forming Minerals, Vol. 3, Longmans, Green and Co. Ltd, London, England (1967) pp. 126-128. 5 OUP 11'0958 DU 054952 New Scientist ^8 June 1978 > 645 No easy solution to asbestos monitoring the proportion of minute fibres the light i microscope misses (winch arc sern tn An expansion of research to develop new sampling technique misses precisely those electron microscopy) are ri>nsi,int)i_ io- and existing techniques for monitoring fibres which the current medical con lated to the number of "visible" fibres. asbestos is called for in the second report sensus believes to be most important in , If it were, measurements by electron of the Health and Safety Commission's causing cancer. microscopy could be relatively easilv con Advisory Committee on Asbestos (HMSO, Despile these faults, the report recom verted to equivalents of phase contrasts 1) Airborne asbestos levels in fac mends that the current technique should measurements. Unfortunately, evidence tories are now measured by drawing air be retained. One reason for this "con- so far indicates the opposite. samples through a membrane filter and servatism'1 is that alternative tnrhnioucs The first report of the advisory com counting the number of fibres trapped are not yftt developed to tne point at mittee. published simultaneously with by phase contrast optical microscopy. The which Lfliy tiutllll be put" into reliable the second, recommends a ban nn technique is simple, cheap and relatively everyday use. Other techniques were sprayed asbestos and on asbestos applied quick. Unfortunately, it also has faults. Tflutltu1, the dust measurements accumu solely for acoustic or thermal Insulation Interlaboratory studies have shown lated so far as part of crucial research (but not on products such as asbestos errors as large as 50 per cent. More projects attempting to correlate exposure cement boards which have other func important, the technique counts only to the development ot disease might be tions). The advisory committee also those fibres visible under an optical invalidated, because the new techniques proposes a licensing system to control microscope -- those down to about 1 are not necessarily compatible. "cowboy" companies installing or strip, micrometre in diameter. The Health and Safety Executive has ping asbestos insulation. II does not These, says the report, "may represent also already acted on another recom recommend that safety representatives only a small proportion of the number of mendation of the advisory committee-- in the insulation industry he given airborne fibres ". Curiously, however, the to measure the sire distribution of fibres greater powers than those in other indus report does not spell out the significance in a range of industrial samples. The tries, as the General and Municipal of this limitation -- that the current point of this exercise is to assess whether Workers Union had demanded. Cl as. .k. DUP y^09S9 DU 054953 TO: J. R. Martin ERD - S&FP 8/22/78 FROM: A. C. HAVEN Ext. 7098 Environmental & Safety Coordinator 4031 Ou Pont Bldg. international Department OOP 1110960 DU 054954 r*'Ojn-A ev s.m ^Y cc: B. C. McKusick - Haskell Lab. C. J. Peters - F. & F. E. I. ou Pont de Nemours & Company JITOWOWATtD Wilmington. Delaware 19896 U. S. A. INTERNATIONAL department CABLE ADDRESS FDRELRONT' WILMDCL August 16, 1978 H. G. DRINKWATER DISA - GENEVA ANALYSIS OF TALC FOR ASBESTOS Ref. Your July 20 letter Enclosed are: 1) OSHA Standard for Asbestos, which describes very briefly the analytical technique to be used in monitoring for asbestos in the workplace atmosphere. Note that an optical microscope is used. 2) Excerpts from a NIOSH criteria document entitled "Revised Recommended Asbestos Standard", which recommends the use of an electron microscope, particularly a transmission electron microscope equipped with electron diffraction facili ties . As I mentioned on the phone, F. & F. are using the opti cal microscope approach, following the OSHA procedure and thus in compliance with the U.S. law. As you know, NIOSH often makes recommendations which are quite conservative relative to what the OSHA people select as a standard, for example, carbon di sulfide and dioxane exposure levels. Thus we feel comfortable at present with the optical microscope method. I therefore recommend you advise Maydown to continue for the present to use this analysis (with another firm if Kelsey Labs, will not oblige), or to send the samples to Marshall Lab, F. & F. if they are unable to get this work done in the U.K. By copy of this letter I am asking Haskell Lab to con sider whether Du Pont for routine control purposes should switeh to the electron microscope method of analysis, as recommended by NIOSH and the Barrot reference. Y/ , /* . A. C. HAVEN ENVIRONMENTAL & SAFETY COORDINATOR ACH:ecd Enclosures DUP t * 1096' DU 054955 IV. SAMPLING METHODS AND ENVIRONMENTAL DATA Review of Sampling and Analysis Techniques for Asbestos A variety of sampling and analysis techniques have been used to identify asbestos fibers and determine their concentrations in air, water, mineral samples, and biologic tissue. These include optical and electron' microscopy, x-ray diffraction, and differential thermal analysis. Asbestos fiber identification and quantitation in occupational and environmental air samples is difficult for a variety of reasons: 1) Asbestos fibers are generally present in low mass quantities even though fiber number concentrations may be high. 2) Many instrumental analytical techniques cannot differentiate asbestos fibers from their nonflbrous mineralogic polymorphs. 3) Many airborne asbestos fibers are generally below resolution limits of the optical microscope. These fibers may only be detected by using electron microscopic methods. &) For identification of the various asbestos fiber types by electron microscopy, electron diffraction and microchemical analyses must be performed which require expensive Instrumentation and analysis time. (a) Electron Microscopy and Microchemlcal Analysis Both transmission and scanning electron microscopy have been used for asbestos fiber identification and quantitation. In addition to morphologic observation, selected area electron diffraction and microchemlcal 58 bup "'0962 DU 054956 analytical techniques may be used for fiber identification. In addition to superior resolution capabilities, most modern transmission electron microscopes are equipped with electron diffraction facilities. Crystalline materials scatter electrons in regular patterns related to their crystal structure. The image of the scattered electrons is mainly predicted by Bragg geometry. In the transmission electron microscope, the diffraction image is formed in the back focal plane of the objective lens and is focused in the viewing screen by defocusir.g the intermediate lens. Visual observation of single fiber (single crystal) electron diffraction patterns may be used to differentiate chrysotile fibers from amphibole fibers (Langer et al, 1974; Timbrell 1970). Chrysotile fibers produce streaked diffraction patterns (lattice defects) , with the streaks or layer lines nearly perpendicular to the fiber length. The spacing between the layer lines denotes the fiber "a" axis of o approximately 5.3 A. Reflections along the layer lines are usually very streaked and Debye-Scherrer rings are common. With progressive electron beam bombardment, the diffraction pattern may change because of fiber damage. The "central core" of chrysotile fibers may also aid in fiber Identification with the precaution that the central core is not always discemable and may disappear with the beam damage (Langer et al, 1974). Also, other fibrous minerals may have hollow cores. The amphibole minerals are generally straighter in appearance than chrysotile fibers. Moreover, light and dark banding (diffraction images) may cross the fiber at right angles (Langer et al, 1974). Diffraction contrast figures have been observed on all amphibole fiber types. Selected area diffraction patterns for the amphibole asbestos minerals are all 59 WP 1110963 DU 054957 similar in appearance; therefore, visual observation of these patterns is sufficient only to classify the fiber as being a fibrous amphibole (Langer et al, 1974; Cook et al, 1974). Amphibole electron diffraction patterns show layers and sometimes streaks perpendicular to the fiber length with the spacing between the layer lines or streaks representing the fiber "c" o axis (Langer et al, 1974) of approximately 5.3 A. In contrast to chrysotile, less streaking along the layer lines is observed with the spot repeat along the lines representing one of the two remaining lattice spacing! ( "b" or "a") depending on fiber orientation relative to the electron beam. Typically, approximately 30 seconds is needed to perform a selected area electron diffraction analysis on a single fiber. In addition to visual observation of electron diffraction patterns for fiber Identification, photographs can be made of the diffraction patterns and crystal "d" spacing! measured from the plate and calculated using the Instrument camera constant (Tlmbrell, 1970). Both "spot" and polycrystalline patterns may be measured. It must be borne in mind that Intensities may not be the same as those observed for x-ray powder patterns and additional reflections may be present. Electron beam microchemical analytical techniques may sometimes be used to Identify asbestos fibers from other fibrous particles (Rubin and Magglore, 1974; Ferrell et al, 1975; Langer et al, 1975; Magglore and Rubin, 1973). The most common system presently in use is the energy dispersive x-ray detector in combination with a scanning or transmission electron microscope. Wavelength x-ray analyzers and the conventional electron microprobe have been used; however, their routine application is limited because of data acquisition times (Langer et al, 1975). On the 60 DUP 1110964 DU 054958 / irtir.il. m-h \ other hand, data acquisition times with energy dispersive analyzers are far less, ranging from 20 to &0 seconds/analysis. Semiquantitative aicrocheaical analysis in the electron microscope is based on the fact that a beam of high energy electrons incident on an asbestos fiber generates x-rays characteristic of the elements present in that fiber. The generated x-rays are observed by means of a detector (lithium-drifted silicon crystal) placed in the electron microscope column close to the specimen. The energy of the x-ray photon is converted to a voltage pulse which is amplified, digitized and stored in a multichannel analyzer or a minicomputer. The content of the memory is usually displayed on a CRT (Maggiore and Rubin, 1973). With the energy dispersive detector, all elements with atomic numbers of sodium or higher may be analyzed. Continuous background or brehmsstrahlung radiation is always present with the x-ray spectrum. Each of the asbestos minerals has an x-ray spectrum which is usually characteristic enough, when combined with fiber morphology, to allow its identification (Rubin and Maggiore, 1974; Ferrell et al, 1975; Dement et al, 1975). Visual observation of the semiquantitative fiber x-ray spectra is usually, sufficient for fiber identification; however, three component diagrams have been used after subtracting the continuous background from the semiquantitative x-ray spectrum (Ferrell et al, 1975). For asbestos fiber analysis, matrix corrections are rarsly used. Typically, iron, magnesium, and silicon are plotted on the three component diagram and compositional boundaries for the asbestos minerals established. This technique suffers from Inability to use all compositional data obtained, such as presence or absence of sodium, calcium, aluminum and manganese, which aid in identification. m DUP 1110965 DU 054959 With energy dispersive x-ry techniques, possession of proper elemental intensities stay not be sufficient for positive identification as many fibrous minerals show similar elemental intensities. For example, chrysotlle, anthophyllite, and fibrous talc, which have similar elemental compositions, may be difficult to differentiate. However, these materials may easily be distinguished by using selected area electron diffraction. In addition, unique identification of the various fibrous amphiboles usually requires both selected area diffraction and microchemical analysis. Transmission electron microscopes equipped with an energy dispersive x-ray detector are now available which allow simultaneous observation of morphology, crystal structure, and elemental composition. These microscopy systems have been used to study asbestos fibers in environmental and material samples. (Cook et al, 1974; Dement et al, 1975) Quantitative analysis of asbestos fiber concentrations in environmental and tissue samples has been accomplished by electron microscopy. Environmental aamples (water and air) are generally collected by first concentrating the sample by filtration, centrifuging, etc (Cook et al, 1974; Nicholson, 1974). The filters (Millipore) and polycarbonate filters (Nuclepore) are prepared for electron microscopic analysis by various methods. For scanning electron microscopy, Nuclepore filters, because of their smooth surface, may be directly coated with an appropriate metal (gold, etc) and analyzed (Porter and Berggren, 1974). Millipore filters have a rough surface texture and are not generally suitable for direct coating for scanning electron microscopy as small fibers may escape detection due to impaction below the filter surface (Nicolson, 1974). 0UP 1U0966 DU 054960 For transmission electron microscopy, the filter substrate must be removed and the particles mounted on suitable electron microscopy grids. A vide variety of mounting techniques have been used. The two most commonly used methods are the Jaffe Wick and condensation washing techniques. The techniques offer simplicity in addition to maintaining the original particle size distribution of the sample. Different investigators have reported particle losses up to 60Z with Milllpore filters while using the condensation washing method with rapid filter dissolution, whereas losses with the Jaffe Wick method have been reported to be considerably less (>10Z) (Beaman and File, 1975). Lesser particle loss has been observed with the condensation washing method when longer times for dissolution of the filter are used. Ortiz and Loom (1974) reported that a modification of the Jaffe Wick method, whereby the filter is first coated with silicon monoxide and carbon by vacuum evaporation prior to dissolving the Milllpore filter, minimized particle loss. Several investigators have reported minimal particle loss with Nuclepore filters when the filter is first carbon-coated prior to dissolving the filter substrate (Cook et al, 1974; Maggiore and Rubin, 1973). In addition to the so-called direct clearing/mounting techniques * mentioned above, many other techniques have also been used' for preparing environmental samples. Seikoff et al (1972) have used a so-called "rubout" technique whereby the Milllpore filter is ashed in a low temperature asher to remove organic or carbonaceous material. The residue is then dispersed on a microscope slide using a solution of 1Z Nitrocellulose in amyl acetate. After grinding with a watch glass to liberate Individual fibers, the sample is dispersed evenly between two microscope slides to 63 DUP 1110967 DU 054961 form a thin fila which is transferred to standard electron microscope grids. Particle losses averaging 50Z have been reported with this technique. This technique also increases the apparent number of fibers present due to breaking up of fiber bundles. Asbestos fiber levels in environmental samples and biologic tissue are usually expressed as asbestos fibers/unit volume of sample (fibers/m3, fibers/liter, fibers/g dry lung, etc). These concentrations are determined by counting fibers within calibrated areas on the electron microscope viewing screen or counting fibers from photographs. Asbestos fiber concentrations in water samples determined by laboratories using the same mounting techniques have been reported to vary by a factor of 2-3 (Cook et al, 1974). Much larger variations have been reported between laboratories using different techniques. Asbestos mass (chrysotile) concentrations in environmental samples have also been determined using electron microscopy. This is accomplished by measuring the length and diameter (volume) of each fiber and calculating the mass using the appropriate density (Selikoff et al, 1972). The accuracy of this technique has not been studied in detail. Electron microscopic techniques represent the "best available" methods for asbestos fiber analysis. However, application of these techniques to routine samples is not practical because of extremely high analysis costs ($200-$400/sample), long analysis times, and limited equipment availability. (b) X-Ray Diffraction * X-ray powder diffractometry is one of the standard mlneralogic techniques used in the analysis of solid crystalline phases. X-ray 64 DUP 1110968 DU 054962 a diffraction baa been widely uaed for identification and quantitation of asbeatoa fibers in bulk materials ouch as talc (Stanley and Norwood, 1974; Rohl and Langer, 1974) and other industrial materials (Crable and Knott, 1968; Keenan and Lynch 1970). X-ray diffraction has also been used to study amphlbole asbestos contamination of water samples (Cook et al, 1974). X-ray diffraction is generally considered more sensitive for asbestos than light microscopy, although less sensitive than electron microscopy (Rohl and Langer, 1974). Diffraction lines and relative intensities for each of the asbestos minerals have been published and may be found in the ASTM Powder Diffraction File. Variations in asbestos fiber chemical composition, especially for the amphiboles, may result in slight peak shifts from reported x-ray diffraction data. Quantitative determinations of asbestos fiber levels in material samples (talc, etc) require that particle size first be reduced to an average of 0.1 - 10 um. Preferred orientation and surface roughness must also be eliminated. A number of techniques have been used to minimize preferred orientation effects including binder and slurry mounting methods, sifting and backloading of dry powders, and several others. To minimize preferred orientation, Rohl and Langer (1974) have developed a method for filtering an aqueous slurry through Millipore filters using a filtration adapter attached to a hypodermic syringe. Other Investigators have used the backloading technique with multiple x-ray diffraction scans. Using conventional scan rates (0.5 - 1 degree 2 theta/minute), lower limits of detection of asbestos by x-ray diffraction of 51 in bulk samples 65 DUP 1110969 DU 054963 hive been reported (Crable end Knot, 1966), Automated step scanning procedures by vhicb diagnostic reflections are slowly scanned and integrated counts recorded have been reported to significantly reduce detectable limits. Rohl end Linger (1974) have detected anthophyllite at 2.0Z, chrysotile at 0.25Z, and treaollte at 0.10X by vleght in a talc matrix using external dilution standards for calibration. Similar lover detectable levels have been reported by Stanley end Norwood (1974). Application of x-ray diffraction for routine asbestos fiber analysis !j of environmental samples has been limited. Birks et al (1975) have reported a feasible study concerning quantitative analysis of airborne asbestos. Their technique involved alignment of the asbestos fibers in an electrostatic field to enhance diffraction intensity followed by x-ray counting in a specially designed diffraction apparatus with two x-ray detectors. A lower limit of detection of 0.4 - 0.5 n% was reported. This ii technique has not been applied to actual environmental samples. Amphibole end cumalngtonite-grunerite mass concentrations in water samples have been semlquantltacively determined using x-ray diffraction with step scanning (Cook et al, 1974). This technique Involves filtering the water through 0.45-fm Millipore filters followed by step scanning a major amphibole diffraction peak (110) and a peak specific to cummingtonitegrunerlte (310). The integrated peak count above background is recorded and mass concentrations are determined using external dilution standards. Proper selection of dlagnoetlc reflections to maximize detection sensitivity and minimize interference due to other mineral phases is necessary for proper use of x-ray diffraction. It must also be recognized m HP 66 Dup H10970 f DU 054964 nlffiiitfc that x-ray diffraction methods are aot capable of differentiating between asbestos fibers and their nonfibrous mineraloglc polymorphs. This fact, combined with relatively poor detection levels, suggests that alternate techniques such as electron microscopy should be combined with x-ray analysis. (c) Differential Thermal Analysis Differential thermal analysis has been used to determine asbestos fiber levels in talc samples (Schlez, 1974) Chrysotile (serpentine minerals) shows a dehydroxylation endotherm at approximately 650 degrees C and an exotherm at approximately 820 degrees C, associated with the formation of forsterite. These peaks may be used for quantitative analysis. Using a 140-mg sample holder with an exposed loop differential thermcouple and a 10 degree C/minute heating rate, Schlez (1974) reported chat a 1% concentration of chrysotile could be detected in pharmaceutical grade talc. A dynamic helium atmosphere was maintained to sweep out gaseous mineral decompoaitlon products and to prevent oxidative reactions. Differential thermal analysis has not been used for environmental samples as lower limits of mass detection are extremely poor. Differential thermal analysia, ilka x-ray diffraction, is not capable of differentiating between asbestos fibers and their nonfibrous mineralogie polymorphs. (d) Optical Microscopy A number of optical microscopic techniques have been used to identify and/or quantitata asbestos fibars in environmental samples. These include petrographic and phase contrast microscopy. Petrographic microscopic techniques may be used to identify asbestos fibers greeter than approximately 0.2 - 0.3 (m in diameter. Using the polarizing microscope, 67 DUP 1110971 DU 054965 various optical crystallographic measurements such as refractive index, extinction angles, and sign of elongation may be measured and compared vlth data reported for standard asbestos reference samples. Typical optical data for selected asbestos minerals are shown in Table IV-1 (Julian and McCrone, 1970). Dispersion staining with polarized light has been used to Identify asbestos fibers, as reported by Julian and McCrone (1974). Vlth this technique, the fibers are immersed in a mounting medium with a steeper dispersion curve than the fibers. A central or annular stop is used in the objective lens bach focal plant to allow either the wavelength of light at which the index of the particle matches that of the mounting media, or complements to that color to reach the observer's eye. Using plane polarized light, asbestos fibers show two characteristic dispersion staining colors; one for the light vibration parallel to and the other for that perpendicular to the fiber length. The dispersion colors depend on the refractive index media in which the fibers are mounted, as shown in Table IV-2. Dispersion staining colors may change slightly depending on the geographic area from which the asbestos was mined and subsequent treatment. Fibers less than 0.5 m in diameter may not be identified by this technique because of difficulties in distinguishing colors. Phase contrast optical microscopy is the technique specified for determining the Occupational Safety and Health Administration asbestos standard (US Department of Labor 1975). The method consists of collecting breathing zone samples during 15-minute to 8-hour periods on membrane filters (millipore AA). Samples are analyzed by first clearing the membrane filter to make it optically transparent, then by fiber counts at 68 DUP 1110972 DU 054966 400-500X magnification by phase contrast optical microscopy. Asbestos fibers are defined as those particles with a length greater than 5 m and a \ length-to-diameter ratio of 3:1, or greater. This technique, by which only fibers longer than 5 m are counted, is recognised as only an index of total fiber exposure and does not imply that shorter fibers do not pose a health hazard. The relative proportion of airborne fibers longer than 5 m has been shown by Dement et al (1975) to vary from 1 to approximately 502 depending on the industrial operation and aabestos fiber type. In addition to problems of detecting short fibers, phase contrast microscopy may not be specific for asbestos fibers in industrial operation where mixed fiber types are encountered. Despite its limitations, phase contrast microscopy represents the only technique available that can reasonably be used for routine asbestos fiber sampling and analysis. It is adaptable to personal sampling where low air volumes are sampled and analysis equipment is readily available. Minimum detectable fiber concentrations by phase contrast microscopy depend on a number of factors such as air volume sampled, microscope field counting area, number of microscopic fields counted, and presence or absence of nonfibrous particles. Theoretical minimum detectable concentrations may be calculated assuming one fiber longer than 5 m is observed per 100 microscopic fields (after filter background subtraction). Table IV-3 shows theoretical minimum detectable fiber concentrations as a function of sample period for a typical microscope arrangement. For a 15minute sampling period, 0.04 fibers >5 um/ce may be detected; however, with an 8-hour sample, 0.001 flbers/cc can be detected. These minimum concentrations are similar to those reported by Corn and Sansone (1974). 69 DUP 1 **0973 054967 These authors reported that 0.01 fibere/cc could be detected with e 2-hour sample period (40 microscopic fields counted). The above calculations represent theoretical minimum detectable concentrations, not considering the many factors affecting precision and accuracy of the technique. There are many sources of variability in the laboratory analysis technique. The major sources of variability are as follows: . 1) Variability of fiber distribution across the filter surface. 2) Variability of fiber distribution on a given filter vedge being analyzed. 3) Variability due to differences between microscopes. 4) Variability due to differences between individual counters. 5) Variability in laboratories. Leidel and Busch (1974) found that the fiber distribution on a given filter section could best be described by the ?oisson-distribucion. However, Conway and Holland (1973) found that the distribution of fibers on filters was not uniform and were more disperse than predicted by the Poisson distribution, so that concentrations between sections could vary by as much as 50-60X. Similar results were found by Rajhans and Bragg (1975) in Series Z of their study. If the Poisson distribution is taken to adequately describe fiber distributions on filter sections, the standard deviation of the fiber count may be estimated from the square root of the count. In order to maintain an*acceptable Coefficient of Variation (CV) (below 20X), a minimum of 25 fibers must be counted. For a typical industrial asbestos sample of 2 70 DUP 111097-4 DU 054968 hours (2 1pm flow), this would correspond to s concentration of 0.13 fibers/cc. The precision of the entire sampling end enelysis procedure (ell sources of variability) has been estimated by Leidel et al (1975). These authors estimated the total CV to be 22%. Comparisons of Asbestos Mass Concentrations (ng/m3) and Fiber Number Concentrations (fibers/cc) In order to relate ambient asbestos levels, which are generally expressed as ng/m^, to occupational exposures, which are expressed as fibers >5 im in length/cc, a conversion factor is needed. Attempts to formulate such a conversion have generally been unsuccessful because of exceptionally large variability. This is to be expected as ambient levels are generally determined using electron microscopy whereas phase contrast microscopy is used to measure occupational exposures. In addition, techniques used to prepare samples for electron microscope observation may cause alterations in fiber size (diameter and length) distributions. Lynch . and Ayer (1966) presented results of environmental studies in the asbestos textile industry where fiber concentrations were determined using phase contrast optical microscopy and fiber size distributions were determined using electron microscopy. The mass of chrysotlle on the filter was estimated by using atomic absorption spectroscopy to determine the magnesium content of the sample and asbestos content was calculated, assuming a 25% magnesium content for chrysotlle. These data are summarized in Table XV-4. Baaed on the magnesium analysis, the authors concluded that 71 DUP 1110975 DU 054969 31:8304 REFERENCE FILE Table Z-2 <c) Methods of compliance--(l) En gineering methods, (i) Engineering con AmMiUhl* niMlinuiu |*ah nl>nv trols. Engineering controls, such os, but t-ftour tint vteghted Aceepuuu eeUinc Ute MMOUbte Ctellll* QOtWOOUt* Uon for on 0-hour iluA. not limited to. Isolation, enclosure, ex haust ventilation, and dust collection, Tap--uiratfoii MaiUuura Quratfoo shall be used to meet the exposure limits prescribed in paragraph (b) of this .......Uciuoti- i/47 4-IMSh ........................................ . 10 p.n.m............. M p.p.m.......... M p.p.m............ lominutao. uaryilitim and baryllmm e*ap*undo .............. ............. MmtautB. (747.20-1070). Caditilmit film* (7474-1870)....... . . 0.lra*7M*. ... Imc./M*............ . Cadmium dust (Z374*1870)................. 0.2 mc^M*. ... 0.0Bf7M*..M..M........................... Carbon dleulMa (747 ....................... 20 p.p.m............ S p.p.m............. WD p.p.m........... 1>0. Carbon mrarHariile CU7.I7-IM7)............ ., 10 p.pju......... . *p-p-............. Mp.pju....... 1 mlnutoa In any 4 t*un. Blhytonadlbromlds(7474l*lf7U).. . p.pjn............ Stepan---------- Mp.pjn............ 1 minutes. BUtylsAS dleiUortdt (JU74I-1MW. . to p.pm............ . MOp.pJS........... 200 ppjs......... .. 1 minute* In any 2 hours. Parmal<)hy<)a (74T.lfr*iwt7). . ................. . > p.p.m.............. p.pj............... * PPJ*............ DaiiituM. Hyrtrovan fluanda (Z*7M-1800>................ Fluortd* aa dust (747.9t-lM.................... Land and tU InarjaMeaompunda (Z47.il- 12 ./.. 1809). Matfeyl oMartta <Z*7.1*-I0M)..................... 100 p.p^.....84Ji . I mlnatea In any S hours. MaUyfom Chkrtda (ZI74-10M)................ M P.PJO........U . ftBlnute* ta Onrana (alkyl) Bavinry (ZI749-10M)......... Ml ./. CM mM ......................... Ityrana (H7.U-1M).................................... lOOp.pjn... Mp.pa.............Mp.pji............ f nlaiatools any I boors, TrtehteraaUyfoa* (ZS7.18-1M7)............ .......da.................... MOp.p.m............ tmiuutsaln any 2 hours, Tatrachlaraaihylaaa (ZJ742-W07)............... . .......do.......................... do................. ft minutes in any S hours. Toiuana (Z3U2-I807)...................................2Mp.p..........MO p.pJt................ M8p.pja............. 10 minute*. 11 ydra*ah ntlflda (ZI7J-IMQ................................................ Mp.p.B..................0p.pja............... 10 minutes eaca only U no section. (ill Local exhaust ventilation, (a) Local exhaust ventilation and dust colcctlon systems shall be designed, con structed. Installed, and maintained In accordance with the American National Standard Fundamentals Governing the Design and Operation of Local Exhaust Systems. ANSI Z2.2-1271, which is in corporated by reference herein. <b> See I ltXO.g concerning ths avail ability of ANSI Z9.2-1271. and the maintenance at a historic file in connec tion therewith. The address of the Amer ican National Standards Institute is given in 11*10.100. (til) particular tools. All hand-op erated and power-operated tools which may produce or releaM asbestos fibers in excess of the exposure limits pre scribed in paragraph (b> of this section, such as. but not limited to. saws, scorers, abrasive whtsU, and drills, shall be pro Mareary (227.1-wm.............................................................. \ BfJlM Chrtmfo odd tad chramaiB (217.7*1071)..................................... da vided with local exhaust ventilation sys tems in accordance with subdivision Ul) On-dfutMaai cspaaum ta fcaaaear art majrrt la tea raguirimeats M ftacuaa 1810 SOtt except as BanficiHyesefMisdbv Sccooa ifti itSKaHSi ripnawraa turnpm y Saco-- ilia lOSStan*) art covert# >y Usa ftacttaa tilt )8M [Foeiseaa to TaMo Z-2 addM 43 FR SH3. Fdmr 10. If7|j______________ of this subparagraph. (2) Work practices--ill Wet methods. Insofar as practicable, asbestos shall be Tabic X.I--Mineral Du#i Kuhtan Mppcf Mf/M* Silica Crystalline* Quartz (raaptrabtei.............. m %SIOH* Quaru (total dost)............... Cristobaltte: U* H the value mkmteUil from Mia 10ac/M*%OIOh*2 OOmc/M* %MOt+2 Aamriynoafo diamatrr (unit OaMlty Mire) l'areant nasaU wfoctor 2 10 1ft 71 110ft Oft 10 0 Tha maaaurasMnu under this natt rater te ths uss af an ABC inatnusant. U tha nsptrabls frsctlan of coal dost H datarmlnad with iURX Uit ileum corraatmndliic U that of 2.4 Mq/M in tha tabto fur ouai dust laid landled. mixed, applied, removed, cut. cored, or otherwise worked in a wet itate sufficient to prevent the emission of airborne fibers in exoass of tha ex posure limits prescribed in paragraph (b> of this section, unless tha usefulness of the product would be diminished thereby. (ill Particular products and opera tions. No asbestos cement, mortar, coat ing. grout, piaster, or similar material count er saaa formulae for quartz. Tndymlte* Use 14 thf valoa nUfiilaiol fntm the for* muter for quartz, Amorphous, ineludmf natural diatemacaou* aarth............. Silicatas (Mb than \% cryv LallliM* tiltFA) Mien......... ........................... $oap*ton............................. Talc (non -aibtstea form > . Talc (fibrous). Use ^battoa limit .. ... Tramoiita (aaa talc, fibrous) Portland cement................. Oraphtte (natural)................. Coal dust (respirable tractlou leas than % 6jOi)................. Kor more than h% dtUj............ t 19iai00l Asbestos. containing asbestos shall be removed from bags, cartons, or other containers (a) DeAnUlant. For the purpom at in which they are shipped, without being this aection, (l) "Asbestos" includes either wetted, or enclosed, or ventilated 29 mmtfw chiyiotUt. amosite, crocidolite, tremo- so as to prevent affectively the release of lite, aathophylliu. and actinolite. %IUt (2) "Asbastoa fibers" maana asbestos flbera loncer than 5 micrometera. airborne asbestos fibers in excess of the limits prescribed in paragraph <b> of this section. A 29* Oft u 2.4BMK' ar lOBC/M* (b) Permissible exposure to airborne concentrations of asbestos fibers--(1) Standard effective July 7, 1172. The l-bour tlma-wslghtad average airbORM concentrations ot aabaitoa flbera to which any employs* may be expoaed (hall not exceed five fibers, lonter than $ micrometers, per cubic centimeter ot air. aa determined by tha method pre (ill) Spraying, demolition, or removal. Employee* engaged in ths spraying of asbaatos. tha removal, or demolition of pipes, structures, or equipment covered or Inauleted with asbestos, and in the removal or demolition of asbestos in sulation or coverings shall be provided with respiratory equipment in accord ance with paragraph (d) (2) (lit) of this Inert nr Nuitaner Dust. UeniHmitir fracUun.... Tout dual............................ %MOri*2 to m IftBCih* Not*' fWmvrroen factor. mppcfxst 3* mutton particles par cubte Boter <parueisi par e.r. Millions of panicMs par ntht* foot of air. baaad an Imptuc*''' samples counted hy U*hi*flwtd ladtnfos. The poreottuca of crystalline SUca in ths formula Is th* amourn determined from aifboma samplas. at* cent m Mum: instance* in which atfcar BtUiadikara bom tbnwn to ba applicable. As determined by iht Bsmbnao filter method at OOxphaB oantmat mortification. Uotii aaneantnUMN) and parennt Quarts iar Ua tpplt* cation of tbs limit ere to lx determined frets ths fraettoa pawnc a use wtectof with tha fallow!nf charactanatka: Contaiouf < 1% qssru; If > 1% quarts, urn Quarts limit. scribed in paragraph <> of this aection. (2) Standard effective July 1, lS7t. The (-hour time-weighted average air borne concentrations ot asbestos fleers to which any employee may be expoaed shall not exceed two fibers, longer than S micrometers, per cubic centimeter of air. as determined by the method pre scribed in paragraph (e) of this section. (2) Ceiling concentration. No em ployee shall be exposed at any time to airborne cencentrations ot asbestos fibers in excess of 10 fibers, longer than 8 micrometers, per cubic centimetar oi air. aa determined by the method pre scribed in paragraph (e) of this section. section and with special clothing in ac cordance with paragraph (d) (3) of this section. (d) Personal protective equipment-- (1) Compliance with the exposure limits prescribed by paragraph (b) of this sec tion may not be achieved by the use of respirators or shift rotation of em ployees, exoept: (i> During the time period necessary to install the aglnearing ocntrols and to institute the work practices required by paragraph (c) of this section; (11) In work situations in which the method* prescribed m paragraph (e) of Occupational Safety A Health Reporter [Sec. ISiaiOOIIdlrillMll ss DUP 1110976 DU 054970 TOXIC SUBSTANCES S-104 31:8305 this section are either technically not feasible or feasible to an extent insuffi the safety or health of the employee or other employees will be impaired by his cient to reduce the airborne concentra use of a respirator. Such employee shall (U) Sampling frequency and patterns. After the Initial determinations required by subparagraph (1) of this paragraph, tions of asbestos fibers below the limits prescribed by paragraph (b) of this be rotated to another job or given the opportunity to transfer to a different po samples shall be of such frequency and pattern as to represent with reasonable section: or sition whose duties he is able to perform accuracy the levels of exposure of em (ill) In emersencles. with the same employer, In the same geo ployees. In no case shall the sampling be dv) Where both respirators and per graphical area and with the same senior dons at intervals greater than 8 months sonnel rotation arc allowed by subdivi ity, status, and rate of pay he had lust for employees whose exposure to ashtfrrs sions (i). (ii>. or (iil) of this subpara graph. and both are practicable, person prior to such transfer, if such a different position is available. may reasonably be foreseen to exceed the limits prescribed by paragraph (b) nel rotation shall be preferred and used. (3> 8pedal dothlng: The employer of this section. (2) Where a respirator la permitted by subparagraph (1) of this paragraph, it shall be selected from among those ap proved by the Bureau of Mines. Depart ment of the Intenor.'or the National In stitute for Occupational 8afety and Health. Department of Health, Educa tion. and Welfare, under the provisions of 30 CFR Part 11 (37 Pit. 1244. Mar. 2S. 1972), and shall be used In accordance with subdivisions ft). (11), (ill), and (lv> of this subparagraph. (D Air purifying respirators. A reusa ble or single use air purifying resolrator. or a respirator described in subdivision ill) or (hi) of this subparagraph, shall be used to reduce the concentrations of airborne asbestos fibers in the respirator below the exposure limits prescribed in paragraph (b) ol this section, when the ceiling or the 8-hour tune-weighted aver age airborne concentrations of asbestos libers are reasonably expected to exceed no more than 10 times those limits. (11) Powered air purifying retpirators. A full facepiece powered air purifying respirator, or a powered air purifying respirator, or a respirator described in subdivision (ill) of this subparagraph, shall be used to reduce the concentra tions of airborne asbestos fibers in the respirator below the exposure limits pre scribed In paragraph (bt of this section, shall provide, and require the use of, spe cial dothlng, such as coveralls or eimiisr whole body dothlng. head coverings, gloves, and foot coverings for any em ployee exposed to airborne concentra tions of asbestos fibers, which exceed the ceiling level prescribed in paragraph (b) of this section. (4) Change rooms: (1) At any fixed place of employment exposed to airborne concentrations of asbestos fibers In ex cess of the exposure limits prescribed in paragraph (b> of this section, the em ployer shall provide change rooms for employees working regularly at the place. (11) Clothes lockers: The employer shall provide two separate lockera or con tainers for each employee, so separated or isolated as to prevent contamination of the employee's street clothes from his work dothee. (ill) Laundering: (a) Laundering of asbestos contaminated dothlng shall be done to as to prevent the release of air borne asbestos fibers In excess of the ex posure limits prescribed In paragraph (b) of this section. (b> Any employer who gives asbestoscontaminated dothlng to another person for laundering shall inform such person of the requirement In (a) of this.subdi vision to effectively prevent the release of airborne asbestos fibers In excess of (3) Environmental monitoring__(1) samples shall be collected from sites of s work environment which ere representstive of the airborne concentrations of asbestos fibers which may reach the breathing gone of employee!. Semples shall be collected on a membrane filter of 0J micrometer porosity mounted in an open-face filter holder. Samples shall he taken for the determination of the 8hour time-weighted average airborne concentrations and of the ceiling con centrations of asbestos fibers. (11 > Sampling frequency and patterns. After the Initial determinations required by subparagraph (1) of this paragraph, samples shall be of such frequency and Pattern as to represent with reasonable accuracy the levels of exposure of the employees. In no case shall sampling be at Intervals greater than 8 months for employees whose exposures to asbestos may reasonably ba foreseen to exceed the exposure limits prescribed in para graph (b> of this section. (4) Employee observation of monitor ing. Affected employees, or their rep resentatives. shall be given a reasonable opportunity to observe any monitoring required by this paragraph and shall have Tsee to the records thereof. (g) Caution signs and labels. (1) Cau when the celling or the g-bour time- the exposure limits prescribed la para tion eigne. (1) Posting. Caution slant weighted average concentrations of graph (b) of this section. shall be provided and displayed at each asbestos fibers are reasonably expected to exceed 10 times, but not 100 times, (c> Contaminated dothlng shall be transported in sealed Impermeable bam, location where airborne concentrations of asbestos fibers may be in excess of the those limits. or other closed, impermeable containers, exposure limits prescribed In paragraph (ill) Type"C"suppiied-atrrespirators, and labeled in accordance with para (b> of this section. Signs shall be posted continuous flow or pressurt-demand graph (g) of this section. -- at such a distance from such a location clatt. A type "C" continuous flow or pres (e) Method of measurement. All de so that an employes may read the signs sure-demand. suppUed-air respirator terminations of airborne concentrations and take necessary protective steps be shall be used to reduce the concentra of asbestos fibers shall be made by the fore snterlnc the ares marked by the tions of airborne asbestos fibers In the membrane filter method at 400-450 X signs. Signs shall be posted at all ap respirator below the exposure limits pre (magnification) (4 millimeter objective) proaches to erase containing excessive scribed in paragraph (b> of this section, when the ceiling or the t-hour timeweighted average airborne concentra with phase contrast Illumination. _ >-- (f) Monitoring--(1) Initial determi nations. within 6 months of the publi concentrations of airborne asbestos fibers. til) Sign specifications. The warning tions of asbestos fiber* are r--onshly cation of this section, every employer signs required by subdivision (1) of this expected to exceed 100 times those limits. shall cause every place of smploymsnt subparagraph shall conform to the re (lv> Establishment of erespirator pro what* asbestos fibers are released to be quirements of 20" x 14" vertical format gram. (a). The employer shall establish a respirator program in accordance with the requirements of the American Na tional Standards Practices for Respira tory Protection, ANSI ZSJ2-1989. which Is incorporated by relersnce herein. b. See 11910.8 concerning the avail ability of ANSI Z88.2-1989 and the main tenance of an historic file in connection monitored in such a way aa to determine whether even) employee's exposure to asbestos fibers is below the limits pre scribed in paragraph (b) of this sec tion. If the limits ere exceeded, the em ployer shell Immediately undertake e compliance program in accordance with paragraph (c) of this section. (2) Perianal monitoring--<l> Sam steas specified in 11810.148(d)(4). and to this subdivision. The signs shall dis play tha following lagsod in the lower panel, with tetter stem and styles of a visibility at least equal to that spectflad In this subdivision. Notation 1" Seas Ssrtf. Oothlc or therewith. The address of the American ples shall be collected from within the Block. National Standards Institute is given in 11910.100. (c) No employee shall be assigned to tasks requiring the use of respirators if, based upon his most recent examination, breathing gone of the employees aa membrane filters at 0.8 micrometer po rosity mounted in an open-face filter holder. Bamplas shell be taken for the determination of the l-hour time- Atom Itseising Dot-- Bqntpnsat. It" Baas 8srU. Ootaic or Block. Ifflotaie. )t" Oothlc. an examining physician determines that weighted average airborne coneantra- Be Net assists la Ana it" Oothlc. the employee will be unable to function tions and of the celling concentrations of normally wearing a respirator, or that asbestos fibers. trains Tour Week Boquins It. 1-20-77 Copyright C 1977 by Tho Bureau of Notionol Afforrt, Inc. [toe. lOiO.IOOHgltllliiH DUP 1110977 DU 054971 # ^31:8306 REFERENCE FILE Legend Notation Brnuuoi AjMaica Dust i point Oolitic. May Be Kutnoui To Your Btaltb. .spacing between mit. snail b at leaat equal to the height of the upper of any lo lines. 2i Caution labels--m Labeling Cau'.ion labels shall be affixed to all raw materials, mixtures, scrap, waste, debris, .uid other products containing asbestos libers, or to their containers, except that no label is required where asbestos fibers have been modified by a bcndin* agent. oauitg. binder, or other material so that curing any reasonably foreseeable use. Handling, storage, disposal, processing, or transportation, no airborne concentra tions of asbestos fibers m excess of the exposure limits presented in paragraph b i of tins section will be released. <u> Label specifications. The caution labels required by subdivision <i> of this subparagraph shall be printed In letters of sufficient sue and contrast as to be readily visible and legible. The label shall -.tote: Caution Contains Asbestos Fibers Avoid Creating Oust Breathing Asbestos Dust May Cause Serious Bodily Harm 'hi Housekeeping--(1) Cleaning. All external surfaces in any place of employ ment shall be maintained free of accu mulations of asbestos fibers if. with their dispersion, there would be an excessive concentration. >2) Waste disposal. Asbestos waste, scrap, debris, bags, containers, equip ment. and asbestos-contaminated cloth ing. consigned for disposal, which may produce in any reasonably foreseeable use. handling, storage, processing, dis posal. or transportation airborne concen trations of asbestos fibers in excess of the exposure limits prescribed in paragraph b i of this section shall be collected and disposed of in sealed imperMeable bags, or other closed, impermeable containers. ' 11 Recordkeeping--(1 > Exposure rec ords. Every employer shall maintain raemds of any personal or environmental monitoring required by this section. Rec ords shall be maintained for a period of it least 20 years and shall be made availcole upon request to the Assistant Sec.cury of Labor for Occupational Safety .md Health, the Director of the Nattoual Institute for Occupational Safety and lic.iltli. and to authorised reprasenluii .es of either. IbiaiOOtiiKI) amended ai 41 1;R 11505. 'I ..ill 19. I (2i Employee access. Every employe* md former employee shall have reasonaiiic access to any record required to be maintained by subparagraph tli of this paragraph, which indicate* the em ployee's own expoeur* to aebeetoe fibers. (3i Employee notification. Any em ployee found to have been exposed at any :.me to airborne concentrations of ashes- os libers in excess of the limits pre scribed in paragraph ibi of this section -nail be notified in writing of the expo sure as soon as practicable but not later .nan a days oi tne lindin*. The employee mail also be timely notified of the cor rective action being token. <J> Medical examinations--(l) Gen eral. The employer shall provide or make available at his cost, medical examina tions relative to exposure to asbestos re quired by this paragraph. (2) P-eplaccr..*nt. -he employer shall provide or make available to each of his employees, within 30 calendar days fol lowing his first employment in an occupation exposed to 'irborne con centrations of asbestos fibers, a compre hensive medical examination, which shall include, aa a minimum, a chest roent genogram (posterior-anterior 14 x 17 inches), a history to elicit symptom atology of respiratory disease, and pulmonary function teiU to lnc'cde forced vital capacity <FVC> and forced expiratory volume at 1 second (FEV,..). (3) Annual examinations. On or be fore January 31, 1973. and at leaat an nually thereafter, every employer shall provide, or make available, comprehen sive medical examinations to each of his employees engaged in occupations ex posed to airborne concentrations of as bestos fibers. Such annual examination shall Include, as a minimum, a chat roentgenogram (postertor-anterlor 14 x 17 Inches), a history to elicit symptom atology of respiratory disease, and pulmonary function tats to include forced vital capacity (FVC) and forced expiratory volume at 1 second (FEVi.). <4> Terminalio o/ employment. The employer shall provide, or make avail able. within 30 calendar days before or after the termination of employment of any employee engaged in an occupation exposed to airborne concentrations of asbestos fibers, a comprehensive medical examination which shall Include, aa a minimum, a cheat roentgenogram (pos terior-anterior 14 x 17 inches), a history to elicit symptomatology of respiratory disease, and pulmonary function tats to include forced vital capacity (FVC) and forced expiratory volume at 1 second (FEV...). <5) Recent examinations. No medical examination Is required of any em ployee. if adequate records show that the employe* has ban examined in ac cordance with this paragraph within the past 1-year period. (6) Medical records--(1) Mainte nance. Employers of employees examined pursuant to this paragraph shall cause to be maintained complete end accurate records of all such medical examina tions. Records shall be retained by employers for at leaat 20 yean. (U) Access. The contests of the rec ord* of the medical examinations required by this paragraph shall be made available, for Inspection and copying. jo the .Visum .Secretary of Labor (or UCCU|ia'io:.a: oifeiy aiv: HeilM I!-,.' D.rt'clur of NfO.'ill to aji.'.r.riet'ii |ihv., and ii.euical cuiivaltim:' at motif af tin in. aim. tii/u.-. t:;e it '. of an <.:q- i"'.i>to or :ormrr ci.-ipiowc. to Ins r.iiys:Mii Altv y iri.ir. who COiiUUtiS .. iiuplicsl ox- 'ni..aiiu!i rtuuirra by this paragraph shall furnish to the employer of the examined employe* all the infor mation specifically required by this paragraph, and any other medical in formation related to occupational ex posure to asbestos libers. I&an 1910.93a .Hldutl.it 36 I It 23207. IjetemImr 7. 1971. cniefeeiKy icniponry a.mu- ud. mut'd as |iurm.inuiil sl.mdjrd .it 17 I l< 11 j I 5. June 7. 1972. v lucnvu 1 uly 7, I v"2. lutluMfitjIu.l Set. 1910.11101 ,il 4U I It '111?"'' May 28. 1975| " 1910.1002 Coal tar pitch volutilee; interpretttioa of term. As used in See. 1910.1000 (Tabic Z.|).cal tar pitch volatila Include the lived poly cyclic hydrocarbons which volatilize from the distillation residua of coal. petroleum, wood, and other organic mat ter. 137 I K 24749 I.ITcellve Nuvemlier 21. I V721 | 19101003 4-Nitrobiphenyl. (a) Scope and application, (l) This section applia to any area In which 4-Nltroblphenyl. Chemical Abstracts Service Registry Number 92933 is manu factured. processed, repackaged, re leased. handled, or stored, but shall not apply to transshipment in sealed con tainers, except for the labeling require ments under paragraphs (e)(2), (3), and (4)of this section. (2) This section shall not apply to solid or liquid mtxturae containing las than 0.1 percent by weight or volume of 4-Nltrobiphenyl. (b> Definitions. For the purposes of this section: (1) "Absolut* filter" is on* capable of retaining 99.97 percent of a mono disperse aerosol of 0.3 urn particles. (2) "Authorized employee'' means an employee whose dutia require him to be In the regulated area and who has been specifically assigned by the employer. (3> "Clean change room" means a room where employees put on clean clothing and/or protective equipment in an environment free of 4-Nltroblphenjl. The clean change room shall be con tiguous to end have an entry from a shower room, when the shower room fscllltla era otherwise required in this section. (4> "Closed system" means an opera tion Involving 4-Nltrobiphenyl where containment prevents the release of 4Nitroblphenyl into regulated areas, nonregulated areas, or the external environ ment. (5) "Decontamination" means the in activation of 4-Nltroblphenyl or its safe (g) "Director" means the Director. National * Institute for Occupational Safety and Health, or any person di rected by him or the Secretary of Health. Education, and Welfare to act for the Director. (7) "Disposal" means the safe re moval of 4-Nltroblphenyl from the work QTirocxxMnte (9) "Emergency" means an tmforseen circumstance or set of circumstances rw- suiting in the release of 4-Nltroblphenyl which may result In exposure to or con tact with 4-NitroblphenyL 9) "External environment" me*hi i environment external to regulated 1 unregulated areas. 10) -r------ a fully tmuitiiw* nfha* thm th Oeeufti*nl 4 HUK Rfrtr (Stc. 1910.1003(b) (10H 20 DUP 1110978 DU 054972 DUP 1110979 DU 054973