An evaluation of short-term exposures to metalworking fluids in small machine shops.

In a study of 23 small machining shops using metalworking fluids (MWFs), real-time air monitoring using an aerosol photometer was performed to investigate the temporal nature of the exposure and to examine the relationship between the instrumental measurements and traditional sampling methods. Time-weighted averages were calculated from the aerosol photometer data and the results were compared to collocated thoracic and 37-mm closed face cassette samplers. The filter samples were analyzed for total mass and the solvent extractable fraction. Depending on the averaging period used, short-term MWF concentrations exceeded 2.0 mg/m3 in 13 to 39% of the plants studied. High short-term exposures were as likely to be found in plants with average concentrations below 0.4 mg/m3 (thoracic-gravimetric) as those above. Regression analyses indicated that the aerosol photometer most closely matched the data obtained from the thoracic fraction of the total mass. In general, the aerosol photometer overestimated the levels determined using the thoracic cyclone and filter, especially when measuring concentrations of water-based fluids. Use of a calibration factor of 0.7 for straight oils or 0.5 for water-based fluids may assist in the interpretation of aerosol photometer measurements if field calibration data are not readily available. Several approaches to determining the calibration factor from field data were evaluated; more complex calibration techniques improved the accuracy of the measurements.

Metalworking fluid exposures in small machine shops: an overview.

Sampling was conducted in 79 small machine shops to assess airborne exposures to metalworking fluids (MWFs). Measured exposures were compared with data from the literature and exposure criteria currently recommended by the National Institute for Occupational Safety and Health and the Occupational Safety and Health Administration MWF Standards Advisory Committee. Sixty-two percent of 942 personal samples collected were less than the recommended exposure limit (REL) of 0.50 mg/m3 for total particulate. However, at least 1 sample exceeded the REL in 61 of the 79 facilities studied; 100% of the samples collected in 10 shops were greater than the REL. Similar trends were found for thoracic particulate exposures where 75% of 238 samples were below the thoracic particulate REL of 0.40 mg/m3. The ratio between thoracic and total particulate for 238 paired samples was 0.55 (r2=0.73). Workers exposed to straight fluids had the highest exposures (GM=0.67 mg/m3) when compared with workers exposed to other classes of MWFs. The highest exposures were measured for grinding and hobbing (GM=0.67 and 0.60 mg/m3, respectively). Measurements using personal impactors indicated that particle size distributions of MWF aerosols had an average mass median aerodynamic diameter of 5.3 microm. Straight oils and soluble fluids tended to be associated with larger particles than were other fluid types; grinding and turning produced the largest particles, whereas hobbing resulted in the smallest. In general, exposures were similar in magnitude and particle size to those previously reported in large automotive plants. Therefore, workers in these small shops may have risks of adverse health effects similar to those demonstrated in the automotive industry.

Comparison of three sampling and analytical methods for the determination of airborne hexavalent chromium.

A field study was conducted with the goal of comparing the performance of three recently developed or modified sampling and analytical methods for the determination of airborne hexavalent chromium (Cr(VI)). The study was carried out in a hard chrome electroplating facility and in a jet engine manufacturing facility where airborne Cr(VI) was expected to be present. The analytical methods evaluated included two laboratory-based procedures (OSHA Method ID-215 and NIOSH Method 7605) and a field-portable method (NIOSH Method 7703). These three methods employ an identical sampling methodology: collection of Cr(VI)-containing aerosol on a polyvinyl chloride (PVC) filter housed in a sampling cassette, which is connected to a personal sampling pump calibrated at an appropriate flow rate. The basis of the analytical methods for all three methods involves extraction of the PVC filter in alkaline buffer solution, chemical isolation of the Cr(VI) ion, complexation of the Cr(VI) ion with 1,5-diphenylcarbazide, and spectrometric measurement of the violet chromium diphenylcarbazone complex at 540 nm. However, there are notable specific differences within the sample preparation procedures used in three methods. To assess the comparability of the three measurement protocols, a total of 20 side-by-side air samples were collected, equally divided between a chromic acid electroplating operation and a spray paint operation where water soluble forms of Cr(VI) were used. A range of Cr(VI) concentrations from 0.6 to 960 microg m(-3), with Cr(VI) mass loadings ranging from 0.4 to 32 microg, was measured at the two operations. The equivalence of the means of the log-transformed Cr(VI) concentrations obtained from the different analytical methods was compared. Based on analysis of variance (ANOVA) results, no statistically significant differences were observed between mean values measured using each of the three methods. Small but statistically significant differences were observed between results obtained from performance evaluation samples for the NIOSH field method and the OSHA laboratory method.

Trends in hearing protector usage in American manufacturing from 1972 to 1989.

This study investigated the trends in hearing protector use in United States manufacturing industries. Using data from the National Institute for Occupational Safety and Health-sponsored National Occupational Hazard Survey (1972), the National Occupational Exposure Survey (1983), and the Occupational Safety and Health Administration-sponsored National Survey of Personal Protective Equipment Usage (1989), estimates were made of numbers of workers using hearing protection in various industries. Unique to this study is discussion of the impact of enactment of hearing conservation regulations during the same time frame as the two earlier surveys. In general, higher percentages of workers utilized hearing protection in 1989 than in 1972. Increased hearing protection use over time was also found when size of facility (number of employees) was taken into account. Differences in the use of hearing protection over the period 1972-1989 varied in individual industries, ranging from less than 10 to more than 30%.

Elevated lead contamination in homes of construction workers.

National Institute for Occupational Safety and Health investigators studied lead exposures among 37 families of construction workers; 22 neighborhood families with no known lead exposures were included for comparison. Workers were identified as having blood lead levels at or above 25 micrograms/dL. This article reports the levels of lead contamination on hands and interior surfaces of homes and automobiles of study participants. Results indicate that the hands of lead-exposed workers were seven times more contaminated with lead compared with control workers; no difference was found between exposed and control family members' hands. Surface lead contamination was significantly higher in automobiles driven by the lead-exposed workers; some locations, such as armrests, were 10 times more contaminated for the exposed group. High lead loadings in lead workers' automobiles were found on the driver's floor (geometric mean [GM] = 1100 micrograms/m2), driver's armrest (2000 micrograms/m2), and passenger's armrest (1200 micrograms/m2). Surface lead concentrations were significantly higher for exposed homes compared with control homes in rooms where work clothing was changed (GM = 370 versus 120 ppm; p = 0.005). While environmental sources of lead were also evaluated, study results strongly suggest that construction workers' occupational exposures together with poor hygiene practices were the primary causes of lead contamination. Requirements intended to prevent "take-home" lead exposures were reported by workers in this study to be infrequently followed by employers. These findings may be limited in representativeness since only highly exposed workers were selected from a specific geographic area. Regardless, targeted education and enforcement efforts are necessary to help ensure that preventive measures are adequately practiced throughout the construction industry.

Mortality of Carpenters' Union members employed in the U.S. construction or wood products industries, 1987-1990.

This study evaluated the mortality of 27,362 members of the U.S. Carpenters' Union who died in 1987-1990. Age-adjusted proportionate mortality ratios (PMRs) and proportionate cancer mortality ratios (PCMRs) were computed using the U.S. age-, gender-, and race-specific proportional mortality for the years of the study. For white male carpenters who were last employed while in construction industry locals, raised mortality was observed for lung cancer (PCMR = 107, CI = 103, 111), bone cancer (PMR = 181, CI = 107, 286), asbestosis (PMR = 283, CI = 158, 457), emphysema (PMR = 115, CI = 102, 130), transportation injuries (PMR = 121, CI = 109, 135), and falls (PMR = 122, CI = 104, 142). For white male carpenters who were last employed while in industrial wood products locals, significantly raised mortality occurred for stomach cancer (PMR = 187, CI = 136, 250), male breast cancer (PCMR = 469, CI = 128, 720), and transportation injuries (PMR = 136, CI = 110, 173). Excess breast cancer was associated with last employment inn wood machining trades. Nasal cancer mortality was not elevated. A total of 121 mesotheliomas were observed. Contributing cause of death analyses revealed raised mortality for these and additional causes; 4,594 (18%) death certificates mentioned occupational and other lung disease as a contributing factor, resulting in significantly elevated mortality. These data show that construction carpenters have moderately elevated mortality for the diseases caused by asbestos (lung cancer and malignant mesothelioma) and from traumatic injuries. The finding of elevated mortality for stomach, bone, and breast cancer was unexpected and requires further evaluation of possible occupational factors. This study confirms that construction carpentry is an extremely hazardous trade. The data suggest that additional preventive action guarding against asbestos exposure and occupational injury is urgently needed in this occupation.

Occupational exposure to noise and ototoxic organic solvents.

The objectives of this study were to review the literature on the effects of occupational exposure to organic solvents on the auditory system and to identify work settings in which exposure to these agents and to noise might occur. The criteria for selecting the chemicals were (a) evidence available that indicated that the chemicals may affect the auditory system and enhance noise effects, and (b) the ubiquity of their use. References to ototoxicity were noted for three proven neurotoxicants, i.e., carbon disulfide, toluene, and trichloroethylene, and for two probable human neurotoxicants--styrene and xylene. The percentages of workers (estimated by NIOSH National Occupational Exposure Survey) exposed to these solvents in each economic sector are shown. Work settings are identified where multiple exposures occur to solvents and noise. The need for future research is discussed.

Job tasks, potential exposures, and health risks of laborers employed in the construction industry.

Construction laborers have some of the highest death rates of any occupation in the United States. There has been very little systematic research focused exclusively on "laborers" as opposed to other workers in the construction industry. We reviewed the English language literature and various data bases describing the occupational tasks, exposures, and work-related health risks of construction laborers. The sources of information included 1) occupational mortality surveillance data collected by the states of California and Washington and the National Institute for Occupational Safety and Health (NIOSH); 2) National Occupational Exposure Survey; 3) national fatality data; 4) cancer registry data; and 5) case reports of specific causes of morbidity. While the literature reported that construction laborers have increased risk for mesothelioma, on-the-job trauma, acute lead poisoning, musculoskeletal injury, and dermatitis, the work relatedness of excess risks for all-cause mortality, cirrhosis, cerebrovascular disease, chronic obstructive pulmonary disease, ischemic heart disease, and leukemia is less clear. Furthermore, while laborers are known to be potentially exposed to asbestos, noise, and lead, and the NIOSH Job Exposure Matrix describes other potential hazardous exposures, little research has characterized other possible exposures and no research has been found that describes the exposures associated with specific job tasks. More advanced study designs are needed that include a better understanding of the job tasks and exposures to construction laborers, in order to evaluate specific exposure-disease relationships and to develop intervention programs aimed at reducing the rate of work-related diseases.

Development, use, and availability of a job exposure matrix based on national occupational hazard survey data.

A job exposure matrix has been developed based on potential exposure data collected during the 1972-1974 National Occupational Hazard Survey (NOHS). The survey sample was representative of all U.S. non-agricultural businesses covered under the Occupational Safety and Health Act of 1970 and employing eight or more employees. Potential worker exposure to all chemical, physical, or biological agents was recorded during the field survey if certain minimum guidelines for exposure were met. The job exposure matrix (JEM) itself is a computerized database that assists the user in determining potential chemical or physical exposures in occupational settings. We describe the structure and possible uses of the job exposure matrix. In one example, potential occupational exposures to elemental lead were grouped by industry and occupation. In a second example, the matrix was used to determine exposure classifications in a hypothetical case-control study. Present availability as well as future enhancements of the job exposure matrix are described.

An examination of occupational medicine practices.

The traditional occupational health on-site utilization of physicians as part of an overall occupational health program has been in decline in recent times. The on-site practitioner is increasingly being replaced by physicians who practice at an off-site location. The effects of this change on the health care delivered to the work force are largely unknown. By utilizing data from the 4490 facilities surveyed during the National Occupational Exposure Survey, it was possible to perform analyses of the association between the on- and off-site practice of medicine and several industrial facility characteristics and services usually associated with occupational medicine. Examination of the data indicated that, in comparison with on-site activity, the off-site practice of occupational medicine appears to result in diminished provision of the screening tests and medical examinations for which data were available.

A genetic study of Hirschsprung disease.

Hirschsprung disease, or congenital aganglionic megacolon, is commonly assumed to be a sex-modified multifactorial trait. To test this hypothesis, complex segregation analysis was performed on data on 487 probands and their families. Demographic information on probands and the recurrence risk to relatives of probands are presented. An increased sex ratio (3.9 male:female) and an elevated risk to sibs (4%), as compared with the population incidence (0.02%), are observed, with the sex ratio decreasing and the recurrence risk to sibs increasing as the aganglionosis becomes more extensive. Down syndrome was found at an increased frequency among affected individuals but not among their unaffected sibs, and the increase was not associated with maternal age. Complex segregation analysis was performed on these family data. The families were classified into separate categories by extent of aganglionosis. For cases with aganglionosis beyond the sigmoid colon, the mode of inheritance is compatible with a dominant gene with incomplete penetrance, while for cases with aganglionosis extending no farther than the sigmoid colon, the inheritance pattern is equally likely to be either multifactorial or due to a recessive gene with very low penetrance. A model of gene action with random effects during morphogenesis is compatible with our observations.

Some trends in worker access to health care in the United States (1974-1983).

As a result of national surveys of occupational health and safety conditions in the American workplace, the National Institute for Occupational Safety and Health (NIOSH) has collected data on the provision of health care to workers as a consequence of their employment. Two of these surveys, initiated in 1972 and 1981, permit a preliminary examination of the trends in worker access to such care. This paper presents data on the provision of some aspects of medical care to workers in manufacturing and nonmanufacturing facilities as a result of employment. Among the principal findings are increases in general health care provided to workers, increased use of off-site physicians, and increased use of screening examinations or tests. Other analyses indicate a decreased use of on-site physicians and pre-employment examinations and decreased industrial retention of health information on new employees.

Compliance with OSHA record-keeping requirements.

The Occupational Safety and Health Act of 1970 requires employers to maintain records of workplace injuries and illnesses. To assess compliance with the law, data from the National Occupational Exposure Survey (NOES) were examined. Of the 4,185 companies with 11 or more employees, 75 per cent maintained OSHA Form 200 designed for recording illnesses and injuries. The number of employees and the presence of a union were positive determinants in the record maintenance. Of companies with 500 or more employees, 95 per cent kept records compared with 60 per cent of companies with between 11 and 99 employees.

Reconstruction of penile agenesis by a posterior sagittal approach.

Penile agenesis is a rare condition requiring gender reassignment and staged perineal reconstruction. This report describes two children reconstructed by taking advantage of the posterior sagittal approach. This approach allows a precise anatomic dissection, construction of a neovagina and accurate positioning of all perineal orifices. We think that this is the preferred approach for this rare condition.

Gastric heterotopia in rectum complicated by rectovesical fistula.

Heterotopic gastric mucosa in the rectum produced a rare complication of rectovesical fistula. Diagnosis was made by direct biopsy and 99mTc scanning. Excision of ectopic gastric mucosa, diverting colostomy, and repair did not result in closure of the fistula. Endorectal pull-through constituted definitive treatment.

Does zonal aganglionosis really exist? Report of a rare variety of Hirschsprung's disease and review of the literature.

The aganglionic segment of intestine in Hirschsprung's disease begins at the anus and extends proximally for a distance that varies from case to case. Occasional reports describe patients in whom the aganglionosis is segmental, with normal distal innervation or a skip area of normal innervation within an area of aganglionosis. This paper describes 4 patients with Hirschsprung's disease wherein a segment of normally innervated colon was found in an otherwise aganglionic colon. Two of these patients were siblings with different fathers. Problems encountered in the management of these patients are detailed. In a critical review of the literature, 2 additional male patients with well-documented zonal aganglionosis were identified. Although variations from the usual morphology or Hirschsprung's disease do exist, they are so rare that they merit clinical consideration only when the anatomic record and the clinical course are in obvious disagreement. Rectal biopsy remains the best method for the diagnosis of Hirschsprung's disease.