Chemical hazards in radiology.

A variety of chemicals are used in medical imaging as developer and fixer ingredients, germicides, and cleaning agents. Glutaraldehyde, a potent sensitizer, may cause occupational skin and respiratory diseases in exposed individuals. Poor ventilation, unsafe practices, and lack of hazard recognition may contribute to occupational asthma and other respiratory disease in susceptible medical imaging personnel. Failure to respond effectively to initial health complaints and reduce exposure levels can have serious consequences for affected employees. It is therefore important for occupational safety and health professionals to alert health facility managers to potential dangers and to recommend effective intervention strategies. When problems are identified, a multidisciplinary team approach is the best method for evaluating and controlling hazards. This team should include industrial hygienists, safety staff, occupational medicine physicians, mechanical and ventilation engineers, personnel specialists, and medical imaging staff. A thorough hazard assessment, medical diagnosis, and administrative personnel actions are critical to effective problem identification and correction. In the case of chemical sensitization, removal of the affected employee may be necessary. By working with designers and equipment installers to monitor compliance with appropriate codes and manufacturers' specifications, hazards can be prevented. We present additional operations, ventilation, and design improvements to reduce chemical exposures to radiology employees.

Colon and stomach cancer mortality among automotive wood model makers.

Automotive wood model makers have been reported to be at excess risk for colon and other cancers in recent epidemiologic studies. To further explore these risks, we conducted a retrospective cohort mortality study, with follow-up from 1940 through 1984, of 2294 white male wood model makers employed at any time until 1980 by three US auto makers. Using US mortality rates for comparison, we found elevated standardized mortality ratios of 1.2 (95% CI, 0.8-1.9) for colon cancer and 1.6 (95% CI, 0.9-2.6) for stomach cancer. We also conducted nested case-control studies for 20 colon and 17 stomach cancer cases and 543 age-matched controls. We found no trend of increased risk for colon or stomach cancer mortality with increased exposure to wood dust or to duration employed in wood model making.

Heart disease mortality among bridge and tunnel officers exposed to carbon monoxide.

The authors investigated the effect of occupational exposure to carbon monoxide on mortality from heart disease in a retrospective study of 5,529 New York City bridge and tunnel officers employed between January 1, 1952 and February 10, 1981, at any one of nine major water crossings operated by the Triborough Bridge and Tunnel Authority of New York City. Among former tunnel officers, 61 deaths from arteriosclerotic heart disease were observed, as compared with 45 expected (standardized mortality ratio = 1.35, 90% confidence interval 1.09-1.68); expected rates were based on the New York City population. Using a proportional hazards model, the authors compared the risk of mortality from arteriosclerotic heart disease among tunnel officers with that of the less-exposed bridge officers. No association of arteriosclerotic heart disease with length of exposure was observed, but there was significant interaction of exposure with age. The elevated risk of arteriosclerotic heart disease among tunnel officers, as compared with that of bridge officers, declined after cessation of exposure, with much of the risk dissipating within as little as five years. The parallel findings of this study of occupational exposure to carbon monoxide and those studies showing the relation of cigarette smoking to cardiovascular mortality suggest that carbon monoxide may play an important role in the pathophysiology of cardiovascular mortality associated with cigarette smoking.

Investigation of solid-phase ozonolysis reactions for use in a personal sampling method for ozone.

Three ozonolysis reactions were tested in the solid phase for reproducibility and quantitative yield of an aldehyde reaction product. The three starting olefins were t-stilbene, 4,4'-dimethoxystilbene and 1,2-di-(4-pyridyl) ethylene which, when reacted with ozone, gave benzaldehyde, p-anisaldehyde and pyridine-4-aldehyde, respectively. The starting olefins were coated on a variety of solid substrates, exposed to known ozone concentrations and then analyzed for the corresponding aldehyde with a gas chromatograph equipped with a flame-ionization detector. The best combination found for all three reactions was with the starting olefin coated on 30/60 mesh Florisil. Consistent yield was obtained for the methoxystilbene reaction within one batch of sorbent; very reproducible results were obtained within four replicate samples for the pyridyl ethylene reaction. No consistency was obtained, however, with any of the reactions between batches of sorbents and between different sets of samples. Several problems were identified which led to the inconsistent results. The t-stilbene and pyridyl ethylene sorbents oxidized over time while stored to form high aldehyde blanks. All three aldehydes, once formed on the sorbent, were volatilized off the sorbent bed as a result of airflow through the bed. Several different solid sorbents were tried unsuccessfully as traps for the purged aldehydes. Finally, lower flow rates resulted in the finding that significant amounts of the aldehydes also were being formed by oxygen in the air sample. Since oxygen was a strong positive interferent, these reactions were considered unacceptable as indicators of ozone.

Industrial hygiene characterization of automotive wood model shops.

A suspicion of an excess cancer risk in automotive model shops prompted the Industrywide Studies Branch, NIOSH, to conduct a proportionate mortality study and an industrial hygiene characterization of operations in these shops. The mortality study showed a statistically significant excess proportion of deaths due to colon cancer and leukemia (for woodshops only). The materials used in the model shops include various natural woods, laminated woods, plastics, resins, varnishes, putties and paints. Personal breathing zone samples were collected for total and respirable dust, amines, various hydrocarbons (including styrene, and toluene), formaldehyde, and nitrosamines. Particle size distribution studies were conducted on the wood dust and bulk airborne samples of dusts were subjected to various mutagenicity test systems. Work practices, ventilation and general housekeeping were checked. Total wood dust samples ranged from 0.03 to 25 mg/m3 with an average around 1.0 mg/m3. The percent respirable dust ranged from 19 to 38% as measured with Andersen impactors. Solvent exposure samples ranged from non-detectable to about 10% of the OSHA Permissible Exposure Levels. Relevant recommendations for improvement of contaminant control were made.

Carbon monoxide exposure from aircraft fueling vehicles.

Investigators from the National Institute for Occupational Safety and Health observed deficiencies in maintenance of fueling trucks at an international airport. The exhaust system is vented under the front bumper, a standard design on fueling trucks which is intended to minimize the proximity of the exhaust system to the jet fuel in the vehicles. Carbon monoxide levels were measured in the cabs of 17 fueling trucks with windows closed, heaters on, and in different positions relative to the wind. One truck had an average CO level of 300 ppm, two exceeded 100 ppm, five others exceeded 50 ppm, while levels in the other nine averaged less than or equal to 500 ppm. Levels of CO depended on the mechanical condition of the vehicle and the vehicle's orientation to the wind. Stringent maintenance is required as the exhaust design is not fail-safe.

A comparison of four personal sampling methods for the determination of mercury vapor.

Four sampling and analytical methods for mercury vapor were compared to each other in terms of precision and accuracy. The four sampling medias used were the 3M passive Mercury Vapor Monitor, the Los Alamos tandem sampling tube, the hopcalite tube, and the iodine impregnated charcoal tube. Six samples from each method were collected at nominal mercury concentrations of 0.05, 0.1, and 0.2 mg/m3. The hopcalite and 3M monitors gave comparable results at all three concentrations while the Los Alamos method gave similar results at the two highest concentrations. The iodine charcoal tube method was the only one exhibiting poor precision when tube loadings were less than 3 micrograms of mercury.

Pattern and model makers, proportionate mortality 1972-1978.

A proportionate mortality study of deceased white male workers in the pattern and model making trades was conducted. Death certificates were obtained for 1257 death benefit-eligible members of the Pattern Makers' League of North America who had died in the years 1972-1978, and age-adjusted proportionate mortality was calculated using 1975 United States white male death rates. For the entire nationwide union, statistically significant excess proportions of deaths were observed due to colon cancer (proportionate mortality ratio, PMR = 167) and to brain tumors (PMR = 211). A statistically significant excess proportion of deaths due to colon cancer (PMR = 163) and to leukemia (PMR = 200) were observed among the members of the predominantly wood shop locals. Nonsignificant excess proportions of cancer deaths occurred at a number of other anatomical sites. Predominant occupational exposures included wood and plastic dusts and epoxy resins in wood shops and cutting oil mists and solvent vapors in the metal shops. These results suggest the need for better work practices in this industry while more definitive studies are completed.

Performance testing of the NIOSH charcoal tube technique for the determination of air concentrations of organic vapors.

The use of the charcoal tube-gas chromatographic method to evaluate workplace air contamination has proliferated greatly in the las 10 years. This report documents early efforts by NIOSH researchers to evaluate several sampling and analytical parameters and their effect on the reliability of the technique. The effects of humidity, sample stability, sample migration and variations in the desorption efficiency are presented. A protocol is suggested for basic testing of the method for new substances.

A solid sorbent personal sampling method for the simultaneous collection of nitrogen dioxide and nitric oxide in air.

A sampling method is described for the collection of air samples containing both nitrogen dioxide (NO2) and nitric oxide (NO) in the range of 0.5 to 5 ppm NO2 and 9 to 50 ppm NO. These two gases are trapped on a solid sorbent sampling tube which employs the collection of the NO2 on a triethanol-amine (TEA)-impregnated molecular sieve surface; the oxidation of NO to NO2 by a solid oxidizer; and the collection of the converted NO on another section of TEA sorbent. The trapped NO/NO2 on each TEA section is desorbed and the concentrations are determined spectrophotometrically. At all concentrations tested, the collection efficiency for NO2 averaged approximately 96%. The collection efficiencies for NO were as follows: at 9 ppm, 97%; at 11 ppm, 106%; at 24 ppm, 84%; and at 50 ppm, 67%.

A summary of the NIOSH evaluation program of portable direct-reading meters.

The National Institute for Occupation Safety and Health (NIOSH) has developed a program to evaluate portable, direct-reading instruments. The results of these evaluations for CO, SO2, combustible gas, and NO2 instruments are reported. Realistic performance specifications have been developed for each of these types of instruments.

A charcoal sampling method and a gas chromatographic analytical procedure for carbon disulfide.

Research is reported concerning an acceptable method for sampling and analyzing samples for carbon disulfide. Test atmospheres of carbon disulfide were generated dynamically using the syringe injection method, ant the theoretical concetnration verified by a liquid absorbent, colorimetric method. The CS2 was adsorbed on charcoal tubes, eluted with benzene, and quantitated with a gas chromatography equipped with a sulfer flame photometric detector. The results compared with the colorimetris analysis. The sensitivity of this method is 1 mug on a charcoal tube. The charcoal tubes were also tested for breakthrough volumes, holding power vs time, and the effect of air transport and temperature cycles.