Document wDvXRGVExggd3GaRV8g5r0R9d

FILE NAME: Weyerhaeuser (WEY) DATE: 1974 DOC#: WEY004 DOCUMENT DESCRIPTION: Unpublished Presentation from Conference with Proceedings / interoffice To: From: Subject: Date: Jill Chris NSC Doc. 9/10/01 1 remember from something 1 did for you a while back that Larry Rogers worked for Weyerhauser in the 70's, though I don't remember when, exactly, Thought you might find this article interesting, H IT cor-' RGENDR SEMINAR -- FRIDAI1. DECEMBER 6, 1974 AlRTEL 8 :3 0 a .m ,-8:55 a,m, Registration 8:55 a,m .-9 :0 0 3 ,m, in tro d u c tio n ................. .Larry PenKava 9:00 a.m, - i0 : l5 a,m, Asbestos & Wood D u s t___Joe W endlick 10:15 a m . -1 0 30 a.m. Coffee 10:30a,iTl.- 11:15a.m. Wood Preservatives, Solvents & FlammaDles . . . . . ........ A! Riegert 11,15a.m.-12:00 Noon Carbon Monoxide .. Peter Breysse 13:00 N oon-1:30 p.m. lu n c h 1.30 p,m. -2;Q0p.m, Formaldehyde & Caustics . . . ........ . Art Schoenborn 2:00 p,m .-2:30p.m , Respirators & Protective E q u ip m e n t....................Walter E. Ruch 2:30 p.m. -3:00 p.m, Instrumentation g C o n tro ls .......................... Donald Ouilici 3:00 p.m. Adjourn a s b e s t o s a n d w o o d DUST by Jos&ph D. wend lick Corporate Industrial Hygienist Weyerhaeuser Company t i mv FART I ASBESTOS What is asbestos ? Asbestos is a member of a group of some 80 naturally-occurring inorganic fibers, which is principally characterized by tuo broad mineral groups, the setpentines and the amphiboles. Only one Significant species of asbestos originates in the serpentine mineral group: chrysotile (a magnesium silicate occurring as long, white flexible, tubular fibers), the chief asbestos of commerce, mined principally in Canada, Italy, Rhodesia, and South Africa, as well as the U.S.S.R, Commercial deposits of asbestos also occur in the U.S. in the states of Vermont, Arizona, and California, Amphiboles (iron silicates), on the other hand, include a number of asbestos species: amosite, croeidolite, antbophyllite, actinolite and tremolile which are mined in South Africa, Australia, Bolivia and Finland. What are the standards? Prior to the Williams-Steiger Occupational Safety and Health Act of 1970, standards on asbestos were primarily directed at minimizing workers1 exposure to within limits thought to cause the debilitating disease, asbestosis. Consider, for example, the level adopted under the WalshHealey Public Contracts Act in 1969, which Set the acceptable limit at 12 fibers/cuhlc centimeter. This asbestos standard was in force until December 7, 1971, when OSRA published an emergency temporary standard concerning exposure to asbestos fibers which lowered the acceptable airborne concentrations in the workplace to* 5 fibers/ce greater than 5 microns in length for an 8-hour time-weighted average (TWA) and 10 fibers/cc greater than 5 microns in length for a ceiling concentration, effective July 7, 1972. NIOSH further recommended that the 5-fiber TWA and 10-fiber ceiling concentrations be permitted only tor 2 years; thereafter, TWA concentrations should be not more than 2 fibers/cc, with no change in the ceiling concentration. OSHA adopted this recommendation in the interest of the health of employees so exposed, such that after July 1, 1976, the acceptable airborne concentrations in the workplace will be: 2 fibers/cc greater than 5 microns in length for an 8-hcur time-weighted average (TWA) and 7 10 fibets/cc greater than 5 mitrons in length for a | ceiling concentration. ! A specification on fiber size was included in the asbestos standards (greater than 5 microns in length) to denote those fibers possessing the greatest fibrogenic and carcinogenic potential. Fibers less than 5 microns in length, according to British studies, do nor exhibit near the. hazardous properties that mark their "greater than 5 micron" counterparts; hence the inclusion of a specific fiber site consideration. i ! What are the hazards? The concern which precipitated the writing, adoption and eventual promul gation, by OSTA, or the emergency temporary asbestos scHndsrd and later the permanent asbestos standard, C7R 1910.93a, was the evidence from several investigators (notably Dr. Irving SelikOff of the Me. Sinai School of Medicine, M.Y.) which indicated a causal relationship between exposure to asbestos and the development of certain types of cancers after a latent (asymtomatic) period or 20-40 years. Medical science has long been cognizant that exposure to airborne asbestos fibers of high enough intensity and long enough duration will lead to a diffuse inorganic dust pneumoconiosis known as asbestosis, Asbestosis is an exposure-related disease which is characterized by interstitial calci fication and scarification, obliterating lung spaces and replacing functional lung tissue with non-functional collagen. It first manifests itself with either dyspnea (shortness of breath) or an irritating dry cough, often over a period of many years. Progressively, as the condition advances, the worker will become increasingly shorter of breath (possibly cyanotic) with death occurring from respiratory failure or heart failure. The more recent revelation, however, that asbestos exposures also increase the risk of: 1) gastric neoplasia (esophagus, stomach and small intestine cancers), 2) bronchial carcinoma (principally among smokers) and finally 3) a rare malignancy, mesothelioma of the pleura or peritoneum, has generated Che most consternation. Because the attack rate of neoplasia among asbestos workers who smoke is 10-12 times higher than workers who smoke but are not exposed to asbestos or who are exposed to asbestos but do not smoke, there would appear to be a synergistic cocarcinogeuic effect involved in the development of bronchial careinoma. It was with regard for the carginogenic effects of asbestos that the standard was lowered. What ptoduCta contain asbestos? Long recognized as a substance possessing desirable fire-resistant characteristics, asbestos fibers have found use in a tremendously broad and diversified array of products. Some, but not all, of the product categories in which asbestos is used are given below; Asbestos-containing blown insulation Asbestos-reinforced magnesia or calcium silicate 3team pipe covering and bluer; insulation Brake shoes 3 - Asbestos-containing grouts and cements Clutch linings of cars Asbestos-cement products/beard Transits pipe Asbestos-reinforced floor tiles Asbestos cloth, blankets, clothing, gloves Asbestos rope Gasketing Asbestos-containing taping for sheet rock joint work Fibrous talcs Filtering medium for wine, gin, etc. Filtering medium for sulfate precipitates (Gooch crucibles) in analytical laboratories What substitute materials are available and can be used? Because of the recognized hazards of working with asbestos-containing materials, especially friable asbestos-containing products, many asbestosfree (but not fiber-free) products have been developed to lessen the asbestos hazard to workers and the general public. Mineral wool fiber or fiberglass fiber-reinforced magnesia and calcium silicate pipe coverings and block insulations are now available throughout the United States in all the shapes and sizes formerly available in asbestos-containing insulativc materials. By example (not to be construed as product endorse ment), the following asbestos-free insulations are on the market: Pabco Super Cal Temp Type NA Johns-Manvilie Thermobestos (Asbestos-free) Kaylo-10 (Asbestos-free) Asbestos has been replaced in grouts and cements also, an example of which is Ryder One-Coat asbestos-free grouting. For products with asbestos bound tightly in a rigid, non-friable matrix such as with brake shoes, clutch linings, asbestos-cement board, most gasketing and asbestoscontaining floor tiles, only a mechanical process such as cutting, sawing, drilling or sanding would represent potentially hazardous work exposures. Ail ocher handling activities could be performed with relative impunity, Asbestos has teen phased cut of laboratory gravimetric analysis schemes in favor of turbidimetry, etc. and is no longer employed as a filtering medium for wine and gin (in. this country). Non-fibrous talcs (no tremolite asbestos) are available to replace the more potentially hazardous fibrous variety. Asbestos cloth, blankets, clothing and gloves are now sur face-treated by the manufacturer to minimise release of asbest os fibers to the work nlic atmosphere. It may well prove to be a false sense of security to assume that mineral wool, fiberglass or ceramic wool are "safe" vis-a-vis asbestos. As our technology improves in the development Of better and (setter synthetic inorganic fibers and fibers approximating the size and chemical composition of naturally-occurring asbestos fibers are produced, these also may possess fibrogenic and even carcinogenic potential. We wouLd be well advised ':v '.hi sane precautions n handling these products reinforced with mineral wool or fiberglass as in the case of asbestos. Row are levels of exposure determined? The accepted technique for evaluating or ascertaining level of exposure is to collect all of the fibers in a known amount of air by passing that air through a filter and then subsequently, by microscopic counting methods, determining the numbers of actual fibers collected in the known air volume. Such a sample must, perforce, be collected in the employees breathing zone in order that the fiber concentration can be related to the individual. Once a determination has been made on the level Of asbestos to width an employee is exposed, qualification for a medical surveillance program can also be evaluated. According to the OSIlA Sampling Method for Asbestos, the samples must be collected across the face of a Millipore Type AA cellulose acetate filter at a sampling rate of 2 liters/minute. Duration of the sample will depend upon the relative concentrations of asbestos and extraneous matrix material in the air at the time of sampling. Attempting to conform rigidly to OSHA's recommended sampling time of 15 minutes minimum duration (in order 1tl to determine violations of the ceiling exposure limit) may result in the ; loss of an important sample because the microscopist Simply cannot get a i reliable count on Che heavily built-up fiber sample on the filter face. Sampling in high visible dust areas should always be started at 2-4 minutes, then 5-7 minutes, 8-12 minutes and finally 15 minutes to minimize loss of samples, particularly if the sampling site is several hundred miles from the counting lab, or more importantly, if the samples taken are representa tive of an event not likely to be repeated on a planned schedule. ; Any industrial hygienists, environmentalists or analysts who are responsible for the calibration Of the personnel sampling pumps, collecting the samples in the workplace and counting the fibers collected on the sampling filters should be aware of and take steps to minimize the errors which can occur at various Stages of sampling and analysis, i,e. - 1) Attitude corrections - a pump calibrated at sea level and u s i i a t - , M 0 f e a t above s e a Level may be o f f io. t h e a c t u a l volume by 3 per cent. * - 5- 2) Cassette orientation. - a sampling cassette resting against a worker's uniform or clothing at the lapel will have a different fiber distribution across the fiber face than one located in the breathing acne but away from the uniront. 31 Ester mixture - the ester mixture used to dissolve away the filter in the counting procedure should be of a consistent concentration and saturated with filter so as to minimize errors in masking fibers with a liquid of similar refractive index. 4) Counting - counts run on wedges cut from the same filter may vary by as much as '30"40 per cent. 5) Microscope - although many microscopes can meet the requirement of phase contrast illumination at 400-450X magnification, microsope resolution varies considerable from brand to brand. 6) Eye - problems of resolution are not just limited to the microscope, the eyes Of different "counters" can also vary. To minimize this error, the same individual(s) should always make the counts. All of these errors can total (by compounding) *40-50 per cent, which means that in order for an inspector to cite a violation of the TWA portion of the present asbestos standard and have it stand up in court, Che TWA should be at least 7.0 - 7.5 fibers/cc greater than 5 microns in length. For the ceiling limit, the values would have to be 14-15 fibers/cc greater than 5 microns in length for, by definition, 3 15minute sample. Conversely, in order for an employer to demonstrate compliance with these limits, typical work place environmental levels would have to be 2.5-3,0 fibers/cc and 5.0-6.0 fibers/cc, respectively. What are some of the asbestos control methods? Various methods of control have been applied successfully to the handling or working with asbestos products to either minimize or eliminate worker asbestos exposure in the workplace. These include, but are not limited to: 1) Wet methods - wetting down asbestos-reinforced insulations prior to demolition or rip-out and, to some extent reapplicatiort will reduce airborne asbestQ3 levels in the breathing tone of affected workers by 80-85 per cent, according to a 1970 publication entitled "Asbestos Exposure and Control at Puget Sound Naval Shipyard" hy Mangold, Beckett and Bessmer. The new proposed regulations on Asbestos by the Environmental Protection Agency for building demolition and renovation stipulate vet-down practices as the asbestos control method Of choice (the only exclusion being contractors who renovate 6 or demolish buildings in sub-freezing temperatures). Unfortunately, alternatives are not permitted, as the proposed regulations now read, to minimize damage to electrical equipment or to other water-sensitive equip ment . 2) Substitution - the use of asbestos fiber substitutes (e.g. - mineral wool, ceramic wool and fiberglass), both alone, in mats or fluff, or as reinforcing fibers in friable magnesia or calcium silicate insulations. Use of non-fibrous talcs, etc, represents other materials which, in most cases, will suffice. To reiterate, however, these synthetic inorganic fiber substitutes may have the same potential for inducing exposure-related disease as with asbestos, 3) Ventilation - two types of ventilation are usually available for control of occupational health hazards: a) general ventilation, and b) local exhaust ventilation. Because of the potentially grave consequences of exposure and all the unknowns as to the precise level of asbestos fibers in air which is safe to breathe without developing a mesothelioma 2O"A0 years later, general ventilation in the control of asbestos is not an acceptable control method {within technical reason and economical feasibility). Local exhaust ventilation, on the other hand, is an excel lent control method for capturing asbestos fibers at the point of origin, For high velocity mechanical operations on asbestos-containing products (drilling, sawing and routing), the high velocity/low volume concept of du$t control (as advocated by Hoffman Dust Control Systems) offers the best means, both economically and technically, for controlling the dust emissions from the power tool. In all cases where a local exhaust ventilation system is used for control of asbestos-containing dusts, a baghouse should be included in the system. Cyclones, even high efficiency cyclones in series, are not efficient enough to control the emissions to the "no visible emissions" requirement of the EfA standard, 4) Handling Practices - while this may seem so insignificant as not to warrant mention, employees handling asbestoscontaining materials (especially dry) in a proper manner can reduce their exposures sufficiently by this route, in conjunction with other engineering controls* to comply with the OSHA standard. 5) Isolation - control by isolation, or enclosure is another way of minimizing or eliminating employee asbestos exposures in the workplace, This method has proven affective in control of carcinogen exposures and radiation (ionizing) exposure. - 7- References: 1. Criteria ot a recommended standard - "Occupational Exposure to Asbestos" - U. 5. Department of Health, Education end Welfare, irstior.al Institute for Occupational ?f U : > End health Criteria Document. 2. Federal Register Volume 37, No. 110 (June 7, 1972), Fart 1900 - Occupational Safety and Health Standards, "Standard for Exposure to Asbestos Duse." 3. "Industrial Ventilation," a manual by the Committee On Industrial Ventilation - Vnerican Conference for Governmental Industrial Hygienists. 4, Mangold, C.A., Beckett, R, R. and Bessmer, D. J. "Asbestos Exposure and Control at Puget Sound Naval Shipyard," Puget Sound Naval Shipyard at Bremerton, Washington (March, 1970). 5, Federal Register Volume 39, No, 208 (October 25, 1974) Part II, Environmental Protection Agency (40 CFR Part 61) "Asbestos and Mercury," Proposed Amendments to National Emission Standards for Hazardous Air Pollutants, PART II WOOD DUST What is wood dust? For the purpose of this paper, wood dust will fine particles resulting from defiberization, or any mechanical cutting or abrasion process dust would be generated from, but not limited be designated as those comminution, trituration performed on wood. This to, the following processes; Woods/Timber lands Cutting and bucking trees Mechanical debarking (ring or Cambium sheer debarkers)' Sawing Wood Products a) Sawmills and Planer mills Sawing at head rig, pony rig, resaw, trim saw and gang saw.