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Industrial Hygiene Forum Franklin D. Griffith, Ph.D. Department Editor The IndustrialHygiene Forum is designedas a medium of exchange for members and readers who wish to share their "know-how" with others yet avoidthe necessity ofprepar ing a full and detailed manuscript on the subject. This is your opportunity to share with others your "know-how," timely tips, new ideas, etc., on any aspect of industrial hygiene. Exceptions are matters of opinion and comments on published manuscripts; these will be published elsewhere in the Journal. Submissions should be signed and markedfor publication in the Forum. Contributions to the Industrial Hygiene Forum will not bepeer reviewed but the right is reserved to edit accepted contributions. The success of the "Forum" of course will depend upon the contributions from you, our readers. For consideration, send your contribu tions directly to Franklin D. Griffith, Ph.D., Industrial Hygiene Forum, AIHA Journal, 475 Wolf Ledges Parkway, Akron, OH 44311-1087, (216) 762-7294. Asbestos Exposure Associated with Automotive Brake Repair in Pennsylvania L. LAMONT MOORE Safety Sciences Department, Indiana University of Pennsylvania, 205 Uhler Hail. Indiana, PA 15705 Introduction Automobile mechanics are potentially exposed to asbestos libers released during brake repair work in service stations, car dealer ships and mulfler shops nationwide. Asbes tos libers are released when service mechan ics clean dust residue Irom contaminated drum or wheel parts. Personal samples were collected from the breathing /ones ol auto mobile mechanics to estimate their asbestos exposure while performing actual brake re moval and repair work. Exposure measure ments were made in thirty-one different facil ities with widely diverse work practices. The estimated average asbestos exposure during actual repair vv ork was <0.03 liber per cubic centimeter (I cc) based on thirty-five sepa rate samples. II /ero exposure were assumed lor the unsampled portions ol these shifts, the mean eight-hour, time-weighted average would have been <0.002 I cc. A 12 Materials and Methods Personal samples were draw n from the breath ing /ones ol employees performing brake service work. Sampling encompassed the entire period required to complete the as signed tasks. In most instances the assign ment consisted of pulling all four wheels, visually inspecting the front disc pads, then removing and replacing both sets of rear brake shoes Each sample was collected on an O.S-gra pore si/e. 25-mm diameter mixed cellulose ester filter mounted in an open-lace. 5-cm diameter cassette. Indiv idual tillers were at tached to the employees' outer garments in the breathing /one. Air was drawn through these filters using MSA Model G sampling pumps. The flow rate on each pump was set at 1.7 Lpm as established by prior calibra tion by a soapbubble meter. The sampling rate was checked periodically and adjusted if necessary to maintain the desired setting. At the conclusion ol each survey , the individual cassette was sealed, labeled and submitted to an approved industrial hygiene laboratory. At the laboratory. a small portion of each filter was cut and mounted on a glass slide in a medium consisting of dimethylphthalate and diethyloxalate. then covered w ith a glass cover slip. Each sample was subsequently counted on a Zeiss microscope equipped with phase contrast and a porton reticle. The reticle is calibrated at a magnification of 400 times with the stage micrometer from Bausch and Lomb Optical with scales of 0.10 mm and 0.01 mm. Results and Discussion One major finding of this study was that automobile mechanics were very well educated about the danger of using compressed air to clean dust from wheel or brake parts. Compressed air was used on a limited basis in only one of the thirty-one facilities surveyed. The data summarized in Fable I suggest that employee exposure typically falls well below the OS HA permissible exposure limit (PEL) ol 0.2 f cc. We point out that these measurements were collected during repairs on a representative number ol vehicle makes and models, in a broad spectrum ol repair facilities employ ing a wide diversity ol work practices. In 75'< of the instances where exposure exceeded the mean (0.03 I cc). poor work practices were involved. Where employees utilized good work practices - such as the use of a spray-type, aerosol liquid cleaner -- seventy percent of the exposure measure ments tell below the mean. Our findings seem somewhat lower than those reported by Kauppincnand Korhonen."' but this may be due to less frequent use of compressed air for cleaning. In most of the Pennsy Iv ania facilities surveyed, each employ ee performed an average of two or three brake repairs per week. Based on our inter views. it w ould be unusual for a mechanic to perform brake service work on more than one vehicle per day. The mean length of time required to com plete these brake jobs was 29 min. If one expects exposure to average <0.03 I cc dur ing this high risk period with zero exposure assumed for the remainder of the shift, the employee's eight-hour, time-weighted aver age could be predicted to average <0.002 f cc on days when brake repairs are under taken. Conclusions Appendix Fto29CFR 1910.1001 summarizes non-mandatory work practices and engineer ing controls for automotive brake repair oper ations.'1 Our study supports OSH As posi tion that management in the automobile serv ice industry can keep employee exposure below 0.1 I cc and avoid costly compliance programs. 1 he most readily accepted, costelfective approach seems to be the use of spray-type, aerosol cans of brake cleaning solvents. I hesecontainersdeiivera mist with considerably less force than shop air hoses fitted with a solvent delivery system. The aerosol spray approach may be equally as TABLE I Summary of Asbestos Exposure Monitoring Number of Exposure Measurements Range for Duration of Sample Period (minutes) Asbestos Concentration' in fiber/cc (Median) (Mean) (Range) 35 10-60 <0 02 <0.03 <001-0.15 'Exposure estimates above reflect actual time-weighted averages for the sampling period during which brake service work was carried out. not the full eight-hour shift. Coayfigrtt !988 American inaustriai Hygiene Association Am Ind Hyg dssoc J (49j January. 1988 HWBUI0012583 eflecltve as vacuum systems equipped with HEPA tillers. provided thai the contami nated liquid drippings are caught in a drip pan and disposed ol in accordance with appropriate waste disposal regulations. Other work practices which deserve man agement consideration include limiting the height ol the car-lilt or service rack so that wheel parts are not disassembled at lor abuse) the level ol the employee's breathing /one and prohibiting employees Irom dump ing dust residue Irom brake drums directly on the shop Hour. Contaminated dust can be vacuumed or carefully dumped into waste liquid containers which subsequently will be used to catch aerosol drippings. References 1 Kauppinen, T. and K. Korhenon: Expo sure to Asbestos During Brake Mainte nance ot Automotive Vehicles by Dif ferent Methods Am. Ind. Hyg. Assoc. J. 40/5j:499-5O4 (1987). 2. 'Asbestos. Tremolite, Anthophyllite and Antinolite." Code of Federal Regulations. Title 29. Subtitle B. Part 1910. Subpart Z. June 20, 1986. Ribavirin -- Exposure to Health Care Workers SUSAN B. LEE Safety Director. The Children's Hospital, 300 Longwood Ave.. Boston, M A 02115 Introduction Ribavirin (l-beta-D-ribofuranosyl-l .2.4 tria/ole-3-carboxamide). an until iral drug, has the Pood and Drug Administration (EDA) approval for administration as an aerosol to selected infants and young children with severe lower-respiratory tract infections due to respiratory syncytial virus (RSV).11' Ribavirin (VirazoleTM) has been sold in Mexico for almost twenty years under the brand name Vilona as an orally administered remedy for viral infections. It is noteworthy as one of several drugs being tested for treatment of AIDS and AIDS related com plex (ARC).1'1 Warnings, contraindications, precautions and a description of adverse reactions are given in the product monograph, as they might affect the patient and the treatment of the disease. Someof the potential adverse health effects lor health care workers administering riba virin may be carcinogenesis, fertility impair ment and fetotoxicity. Use of the drug is contraindicated in women or girls who are pregnant or may become pregnant during exposure to ribavirin. Ribavirin has been found to beteratolethal and, orembryolethal in nearly all animal species in which it has been tested. It has shown structural and meta bolic similarity to other cytotoxic agents, is mutagenic in mammalian cell culture and has caused cell transformation in an in vitro mammalian system. The purpose of this paper is as follows: to describe the method of administra tion of aerosolized ribav irin as the source of occupational exposure to the drug: to describe policies and procedures dev el oped by one hospital in the absence of any data on the level of exposure, given Am Ind Hyg Assoc J (49) January. 1988 employee complaints of irritation and concerns about reproductive toxicity: to report results o! environmental mon itoring lor airborne ribavirin. Administration of Ribavirin A sterile dilution of lyophili/ed ribavirin is prepared such that the concentration of the solution is 20 mg mL. The small-particle aerosol generator (SPACi-2) delivers the solution as a small, uniform size aerosol (S)5ff of particles < 5 yu diam)"' which is "contained" inside a hood or tent around the patient's breathing zone. The average aero sol concentration for a 12 hr period would be 190 yug, l. (0.19 mg, L.) of air. The aerosol is administered for 20 ot 24 hr for five consecutiiedays. Occupational Exposure Direct exposure occurs w hen nurses, respira tory therapists, doctors or others actually enter the tent to care for the patient. Because these patients are usually very young and quite ill. the tasks involved in caring for them may be quite frequent and of relatively long duration (15 min to I hr at a time). It should be noted that the care is to a "babe in arms." and this exposure is in the employee's breath ing zone. Indirect exposure may occur because the tent or hood is not an airtight filtered system. The pressure inside the tent is positive with respect to the room. and. therefore, the air borne ribavirin particles may leak into the room creating potential for inhalation to anyone entering the room. Direct caregivers who may enter and leave the room to check on the patient's status, without entering the tent, may be exposed in this way. The greater concern of indirect exposure is to the par ents, who may visit anytime day or night and who may spend the entire night in the patient's room. Employees'complaints of headaches, burn ing and dryness of the eyes, coughing and dryness of the upper respiratory tract resulted in the Safety Office's becoming involved in in vestigating the matter of occupational expo sure to ribavirin. Since the majority of the Copyngm tges American inausinai Hygiene Association exposed health care workers are women in their child bearingyears. the potential lor tela I death or damage was o! even higher concern than the above-mentioned acute symptoms. Method and Results In the absence of any data on the level ol exposure and to most prudently address the potential hazard to unborn children of stall members, it was recommended that preg nant workers (or those attempting to become pregnant) be excluded Iromany exposure by not caring tor patients on ribai irin. In response to the acute symptoms de scribed above, an industrial hygiene survey was conducted using a calibrated licndtx pump, open-face, 37 mm cassettes and 0.8 gMCEE. Preliminary results showed ambi ent exposure levels of 2.35 to 2.80 mg m' airborne dust. Based on these results and assuming the "dust" was ribav irin. the Safety Office required the following protection for stall who enter the room while ribavirin aerosol was being administered: to prevent eye irritation goggles: tight-litting to prevent inhalation approved dust mist respirators(3M Company 8710. or equivalent) properly worn and fitted; to prevent inadvertent ingestion use ol long-sleeved gowns and latex gloves, scrupulous personal hygiene, hand and any exposed skin surlaee washing: toassureemployees understand potential hazards, routes ol entry and limitations of protective measures dissemination of product literature and training sessions. Using an identical method and collecting five additional samples, we (at the Children's Hospital) were unable to confirm theairborne dust concentration seen in the first two sam ples. All other samples were below the limit of detection in exposed and non-exposed areas. Based on these results, the requirement for strict use ol personal protective equipment was limited to the occasions w hen employees enter the tent. A-I3 HWBUI0012584