Evaluation of pulmonary function in workers exposed to hexamethylene diisocyanate.

Production of hexamethylene diisocyanate (HDI) biuret and trimer from HDI monomer was started in 1988 at the plant under study. Pulmonary function tests were included as part of the annual evaluation of the workers in that unit. HDI is expected to have toxic properties similar to those of toluene diisocyanate. The latter has caused accelerated declines in pulmonary function in exposed workers. In 1991, an initial longitudinal evaluation of those pulmonary function tests was performed, comparing annual declines in forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1). The purpose of the study was to evaluate whether or not exposures to HDI at the unit had caused any accelerated decline in FVC or FEV1. No significant differences were seen in that evaluation, but it was decided that the study be continued in a prospective fashion. The study has been continued through 1997. The slope of the annual change in FVC and FEV1 were calculated for a group of workers and a matched control group. The average annual decline in FVC for the exposed group (cases) was 0.026 L, compared with 0.025 L for the control group. For the decline in FEV1, the results were 0.044 L, compared with 0.041 L (P = 0.79). These results are virtually identical and support a conclusion that exposures within this unit to HDI have not caused an accelerated decline in FVC or FEV1. Exposures to HDI were measured during this period. The time-weighted average exposure to HDI during work not requiring respiratory protection in the unit (approximately 2 hours per day) was 0.5 parts per billion. The average daily high peak exposure was 2.9 parts per billion. Exposure to these levels appear to pose no risk of accelerated decline in pulmonary function.

Medical programs for multiple domestic sites. An in-house perspective.

The author was asked to share his experiences in developing medical programs within a company with numerous small manufacturing locations. Successful programs at these locations depend on obtaining high-quality occupational medical services in the local community. Policies that drive the content and quality of medical program services within large companies are described. Factors that are important in selecting and retaining a local provider are discussed in detail as is the ongoing role of the company's medical director in local site medical programs. The importance of program reviews or audits is stressed with information presented on what a private clinic or practitioner should expect during an audit. Impartiality, objectivity and fairness were emphasized along with the need for good office management and interpersonal skills as characteristics that can help lead to long-term business relationships between corporate clients and occupational medicine physicians in private practice.

The effects of compliance cost and specific consequence information on the use of safety equipment.

The effects of compliance cost and warning content on the use of protective eyewear by racquetball players were evaluated. Four-hundred-twenty subjects were observed for use of eye protection in a field setting. Results indicate that proximal placement of eyewear and the inclusion of specific consequence warning information increased safety equipment use. Implications of this research for augmenting warning effectiveness and safety are discussed.

Role of epidemiologic studies in evaluating the carcinogenicity of chromium compounds.

Epidemiologic and animal studies have identified intermediately-soluble chromates as human carcinogens. Epidemiologic studies also provide moderately strong evidence to conclude that chromates do not cause cancer at sites other than the respiratory tract. This information, combined with the evidence from animal studies and in vitro experiments, has led to the conclusion that chromates do not present a carcinogenic risk from ingestion. Unfortunately, epidemiologic studies have not provided definitive answers to other questions: (i) does trivalent chromium present a cancer risk?; (ii) is there a threshold for carcinogenic effects?; and (iii) what is the appropriate model for predicting cancer risk? Mechanistic research with supporting evidence from animal studies has provided the most useful information to answer these questions. Working hypotheses are: (i) trivalent chromium is not a carcinogen; (ii) there are probably substantial differences in carcinogenic potency between chromates, with the water-soluble compounds having lower potency than intermediately-soluble compounds; (iii) only respiratory tract cancers are caused by exposure to chromates, and ingestion and chromates does not constitute a carcinogenic risk; (iv) there is probably a threshold for carcinogenic effects from chromium due to detoxification mechanisms and lack of bioavailability of low doses; and (v) currently used models for quantitative risk assessment (e.g. the low dose linearized multi-stage model) are inappropriate to predict low dose cancer risks from exposure to chromates.

A comparison of currently used serum lipase and amylase procedures in the serial detection of enzyme elevations in acute pancreatitis.

Twenty-eight patients having acute pancreatitis were followed during convalescence with serum amylase and lipase determinations. Starch and p-nitrophenyl-oligosaccharide substrates were used for amylase. Dimercaptotributyrate and triolein were employed for lipase. The extreme sensitivity of the lipase procedure using the tributyrate detected a persistent elevation of lipase when other parameters of measurement had returned to normal.

Urinary cytologic examinations of laboratory workers. Useful medical surveillance tool or clinician's nightmare?

An apparent excess of abnormal urine cytological findings in crime laboratory workers exposed to potentially carcinogenic aromatic amines was investigated by a cross-sectional epidemiologic study comparing these workers with an unexposed control group. The prevalence of atypical findings in the laboratory workers exceeded that in the control group; however, the results were not statistically significant. A number of serious problems were identified including a high prevalence of inflammatory changes (25% to 26%) and a moderately high percentage of atypical changes (2.5% to 5.4%) in the control population, failure to detect (on urological workup) evidence of neoplastic disease of the urinary tract in any of the laboratory workers whose urine examinations were cytologically interpreted as either atypical or neoplastic cells, and difficulty in determining proper referral criteria for urological workup.

Urine cytology as a medical surveillance tool: a study of variability in interpretation of urine cytology slides.

This study examines the value of urine cytology as a medical surveillance technique in the industrial setting through an evaluation of the variability in interpretation of urine cytology slides. Urine samples were collected from 259 individuals for cytological examination. The slides were read by pathologists and screeners at one large Army medical center and separately read again by an independent pathologist at another Army medical center. The two independent readings for each of the 259 cases were compared. The comparison indicated that overall agreement was fairly high in reporting the presence or absence of inflammatory cells, red blood cells, and atypical (including metaplastic) cells. However, considering positive findings of the presence of red blood cells or atypical cells only, significant differences between the two independent readings were noted when the sign test was applied. Implications of these findings are discussed in light of the use of urine cytology as a medical surveillance tool in occupational medicine.

Ocular medical surveillance on microwave and laser workers.

Results of over 800 medical surveillance ocular examinations on microwave and laser workers were evaluated using multiple regression analysis techniques. No lenticular or retinal defects were noted that could be attributed to work with either microwave or laser radiation. Increased incidences of minute lenticular defects were noted with increasing age. A high variability in the recording of such defects at different locations was attributed to differences in the subjective evaluation of individual examiners. It was concluded that periodic medical surveillance as conducted on the microwave and laser workers under study was nonproductive and suggestions were made to limit medical surveillance for these worker groups to preassignment, postaccident exposure, and termination eye examinations.

Trinitrotoluene: a review of reported dose-related effects providing documentation for a workplace standard.

The scientific and medical literature on TNT was reviewed with emphasis on studies providing correlation between work exposures and adverse health effects. Numerous adverse effects including upper respiratory and gastrointestinal complaints, anemia, liver function abnormalities, and possibly aplastic anemia have been noted at TNT levels below the current standard of 1.5 mg/m3. Mild biological effects, particularly reduction in hemoglobin levels or red blood cell counts, have been noted at exposures as low as 0.2 mg/m3. A workplace standard of 0.5 mg/m3 as an 8 hour time-weighted exposure is suggested for protection against adverse health effects.

Absence of health hazards associated with RDX manufacture and use.

A cross-sectional spidemiologic study was conducted to investigate a cluster of three cases of systemic lupus erythematosus at one munitions plant. The study demonstrated no excess of autoimmune disease and also failed to identify any abnormalities of the hematologic, hepatic, or renal systems in employees with 8 hour time-weighted exposures to RDX of up to 1.57 mg/m3 (average exposure was 0.28 mg/m3).

Biological effects of trinitrotoluene from exposure below the threshold limit value.

Statistically significant rises in serum glutamic oxalacetic transaminase and lactic dehydrogenase determinations occurred at exposures to TNT of 0.8 mg/m3 and persisted at exposures of 0.6 mg/m3. Based on these findings, the adequacy of the current threshold limit value for TNT (1.5 mg/m3) is questioned.