Interstitial fibrosis following hydrogen sulfide exposure.

This case report describes a patient with interstitial fibrosis 4 years after poisoning by hydrogen sulfide. Hydrogen sulfide causes pulmonary edema and is also toxic to the nervous system. Long-term pulmonary sequelae of hydrogen sulfide poisoning has not been reported frequently in the literature.

Fatal unintentional occupational poisonings by hydrofluoric acid in the U.S.

BACKGROUND: Case reports have identified hydrofluoric acid (HF) as causing fatal work injury, and HF has both local and systemic toxicity. Surveillance for HF-related mortality is problematic because of the lack of unique coding for this acid in hospital records and vital statistics. METHODS: We identified HF-related fatal work injuries investigated by the Occupational Safety and Health Administration (OSHA) for 1984-94 from coding of Hazardous Substance 1460 (HF) and requested case investigation files under the Freedom of Information Act. We attempted to identify HF-related deaths in the US for the same period through literature case reports, the Consumer Product Safety Commission, and the American Association of Poison Control Centers (AAPCC). RESULTS: For the 11 year period, OSHA investigated nine deaths in eight incidents which involved HF. Four deaths were from skin contact with concentrated HF, and five deaths involved both skin contact and inhalation of vapor. Unsafe work practices were factors in all of the deaths. Calcium chloride or gluconate was noted to have been administered to five of the nine victims. Calcium was administered 90 min after exposure to two victims, and more than 6 h after exposure to a third. We were able to establish that the regional poison control center had been contacted in regard to only one victim. For the period 1984-94, we were able to identify no additional deaths from CPSC reports, one additional death from AAPCC annual reports, and four other deaths from case reports in the medical literature. CONCLUSIONS: For the period of this study, OSHA records identified the greatest number of HF-related fatalities. The limited information in the records suggest that some victims did not receive appropriate medical care, nor was the regional poison center contacted regarding care. The full extent of health problems related to HF could be better quantified if usual surveillance sources, such as vital records, included unique coding for this acid.

Occupationally related hydrogen sulfide deaths in the United States from 1984 to 1994.

Alice Hamilton described fatal work injuries from acute hydrogen sulfide poisonings in 1925 in her book Industrial Poisons in the United States. There is no unique code for H2S poisoning in the International Classification of Diseases, 9th Revision; therefore, these deaths cannot be identified easily from vital records. We reviewed US Occupational Safety and Health Administration (OSHA) investigation records for the period 1984 to 1994 for mention of hazardous substance 1480 (hydrogen sulfide). There were 80 fatalities from hydrogen sulfide in 57 incidents, with 19 fatalities and 36 injuries among coworkers attempting to rescue fallen workers. Only 17% of the deaths were at workplaces covered by collective bargaining agreements. OSHA issued citations for violation of respiratory protection and confined space standards in 60% of the fatalities. The use of hydrogen sulfide detection equipment, air-supplied respirators, and confined space safety training would have prevented most of the fatalities.

Occipital lobe meningioma in a patient with multiple chemical sensitivities.

BACKGROUND: The concurrent diagnosis of meningioma with increased intracranial pressure has not been reported previously in a patient who meets diagnostic criteria for multiple chemical sensitivities (MCS). METHODS: A patient who had been evaluated in an occupational medicine practice, and by several other physicians for sensitivity to chemical odors was found to have papilledema and a visual field deficit. The patient met the clinical criteria set forth by Cullen in 1987 for MCS. A magnetic resonance imaging (MRI) scan was performed. RESULTS: The MRI revealed a large occipital lobe meningioma, which was surgically resected. Removal of the meningioma had little effect on the patient's symptoms. She has been unable to return to her job as a custodian. DISCUSSION: The etiology of MCS has been disputed and is currently unresolved. Those who evaluate patients with MCS are reminded that meningiomas and other intracranial mass lesions can affect olfaction, and that patients with MCS can have treatable intracranial abnormalities.

Distinctive emergency department usage for injury for workers' compensation cases in Utah in 1996.

To compare emergency department services paid by worker's compensation (WC) with services paid by other payers, a state database of 72,747 emergency department visits for injured adults (ages 21 to 54) in 1996 in Utah was analyzed. WC visits accounted for 21.6% (15,704) of all adult injury visits. The mean emergency department charge for WC visits was $282, and the admission rate was 17 per 1000 visits. The mean charge for other payers was $334, and the admission rate was 43 per 1000 visits. Differences were also found between these groups for Injury Severity Scores and diagnoses. In summary, WC emergency department usage was associated with less severe injuries than was emergency department usage for other payers in Utah in 1996.

Health effects associated with sulfuryl fluoride and methyl bromide exposure among structural fumigation workers.

OBJECTIVES: This study assessed the health effects associated with occupational exposure to methyl bromide and sulfuryl fluoride among structural fumigation workers. METHODS: A cross-sectional study of 123 structural fumigation workers and 120 referents in south Florida was conducted. Nerve conduction, vibration, neurobehavioral, visual, olfactory, and renal function testing was included. RESULTS: The median lifetime duration of methyl bromide and sulfuryl fluoride exposure among workers was 1.20 years and 2.85 years, respectively. Sulfuryl fluoride exposure over the year preceding examination was associated with significantly reduced performance on the Pattern Memory Test and on olfactory testing. In addition, fumigation workers had significantly reduced performance on the Santa Ana Dexterity Test of the dominant hand and a nonsignificantly higher prevalence of carpal tunnel syndrome than did the referents. CONCLUSIONS: Occupational sulfuryl fluoride exposures may be associated with subclinical effects on the central nervous system, including effects on olfactory and some cognitive functions. However, no widespread pattern of cognitive deficits was observed. The peripheral nerve effects were likely caused by ergonomic stresses experienced by the fumigation workers.

Ergonomic risk exposure and upper-extremity cumulative trauma disorders in a maquiladora medical devices manufacturing plant.

Workers at a Nogales, Mexico, maquiladora plant that assembles medical devices were studied to determine the prevalence of upper-extremity cumulative trauma disorders (CTD). Subjects included production workers employed 6 months or longer; of the 148 eligible workers, 145 (98%) participated. Subjects had a mean age of 24.6 years (SD = 5.2; range, 17 to 45) and the mean length of employment was 3.5 years (SD = 2.5; range, 0.5 to 14). Job tasks were videotaped and analyzed for ergonomic risk factors, using pre-defined criteria. All jobs performed by study subjects were found to involve one or more ergonomic risk factors associated with the development of CTD. A CTD questionnaire and screening physical examination format, similar to that used by the National Institute of Occupational Safety and Health (NIOSH) in a chicken processing plant study, were administered. Period prevalence of CTD within the previous year, as reported on the questionnaire, was 28%. Prevalence of CTD was 17%, using data from the screening physical examination. Point prevalence (current pain data from the questionnaire plus positive symptoms on the screening physical examination) was 15%. CTD was reported more frequently in women than men (46% and 25%, respectively; P < 0.05) and in subjects who had worked at the plant less than one year (50%; P < 0.05). Workforce turnover (3% monthly) may have resulted in those affected by CTD leaving employment, reducing the apparent CTD rate in experienced workers.

Age and fatal work-related falls.

In the work environment, an increased risk of fatal injury from falls is seen at ages not normally considered to be old. This study examined fatality data from a National Institute for Occupational Safety and Health death certificate database and from Occupational Safety and Health Administration (OSHA) investigations to analyze the relationship of age to fatal work-related falls. For 1980 to 1986, death certificates reported 43,505 fatal work injuries in men, 4179 of which were from falls. Fatality rates from falls showed an increase for older workers beginning with the age group of 45-54, whereas fatal injury rates for other work-related causes did not increase until the age group of 55-64. OSHA investigations of 996 fatal work-related falls in 1984-1986 reported that falls from ladders accounted for 20% of fatal falls in workers aged 55 and over, significantly more than the average of 9% of all falls for workers of all ages. OSHA data also showed that fatal falls among older workers were associated with lower energy of impact, which means that the height of fatal falls tends to decrease with increasing age.

Identification of soft tissue sarcoma deaths in cohorts exposed to dioxin and to chlorinated naphthalenes.

Identification of soft tissue sarcomas (STSs) in epidemiologic mortality studies is complicated by nosologic coding rules that require that STSs arising in a visceral organ must be coded in the International Classification of Diseases (ICD) category for that organ, rather than in the ICD category for malignant neoplasms of connective tissue. Moreover, prior studies have shown poor agreement between diagnoses recorded on death certificates compared with those in hospital records for these tumors. We reviewed deaths from STS among workers in a registry of 6,716 dioxin-exposed workers at the National Institute for Occupational Safety and Health (NIOSH) and in a NIOSH cohort mortality study of 10,240 workers exposed to chlorinated naphthalenes. We identified 19 subjects with STSs. Of these, 17 (89%) were identifiable by reading the entries on selected death certificates, and two (11%) were found only by reviewing medical records of cases coded to ICD categories likely to have contained STS. Of the 17 STSs identified from death certificates, only nine (53%) had been coded as underlying cause of death to the ICD category "malignant neoplasms of soft and connective tissue." Medical records were obtained for 14 of the 17 cases (82%), and in each case, the STS diagnosis was verified. Tissue blocks from tumors were available for review in nine of the 17 cases identified from death certificates, and the diagnosis of STS was verified in seven (78%). Nosologic rules reduce the sensitivity of cohort mortality studies to detect excesses of STS.(ABSTRACT TRUNCATED AT 250 WORDS)

Work-related deaths in construction painting.

Analysis of investigation records of the United States Occupational Safety and Health Administration (OSHA) concerning work-related deaths in Standard Industrial Classification (SIC) 1721, construction painting, showed a higher risk of fatal injury than expected from cohort studies including injuries on and off the job. Work-related death rates were 2.3 x 10(-4)/year (ie, three to five times that of general industry). Of the 129 deaths investigated, the largest category was falls (N = 65), followed by electrocution (N = 40) and asphyxiation from solvents or oxygen deficiency (N = 6). Eighteen deaths had other causes. The average OSHA fine for the employer was USD 607.00/fatality. Only 31% of the deaths occurred at firms covered by a union contract. Risk of fatal injury was the highest for small firms with fewer than 10 employees. Cohort mortality studies based on records from unions or large employers probably exclude many small firms and so underestimate the risk of fatal injury to painters.

Fluorocarbon 113 exposure and cardiac dysrhythmias among aerospace workers.

We investigated the cardiotoxic effects of 1,1,2-Trichloro-1,2,2- Trifluoroethane (fluorocarbon 113 or FC113) exposures among healthy workers cleaning rocket and ground support equipment for the National Aeronautic and Space Administration (NASA) programs. Exposure and ambulatory electrocardiographic (ECG) monitoring data were evaluated on 16 workers, each of whom was examined on exposed and nonexposed workdays. We examined whether there was a greater rate of dysrhythmias on an exposed workday relative to a nonexposed workday. Overall, we found no within subject differences in the rate of ventricular and supraventricular premature beats (number per 1,000 heart beats), fluctuations in the length of the P-R interval, or heart rate. We found that levels of FC113 exposures below the Occupational Safety and Health Administration (OSHA) 8-hour time-weighted-average (TWA) standard of 1,000 ppm did not induce cardiac dysrhythmias or subtle changes in cardiac activity. However, because fluorocarbons may sensitize the heart to epinephrine, this study's negative findings based on sedentary and fairly healthy workers may not be generalizable to other populations of workers who are not as healthy or engaged in more physically demanding work.

Cancer mortality in workers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

BACKGROUND: In both animal and epidemiologic studies, exposure to dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, or TCDD) has been associated with an increased risk of cancer. METHODS: We conducted a retrospective cohort study of mortality among the 5172 workers at 12 plants in the United States that produced chemicals contaminated with TCDD. Occupational exposure was documented by reviewing job descriptions and by measuring TCDD in serum from a sample of 253 workers. Causes of death were taken from death certificates. RESULTS: Mortality from several cancers previously associated with TCDD (stomach, liver, and nasal cancers, Hodgkin's disease, and non-Hodgkin's lymphoma) was not significantly elevated in this cohort. Mortality from soft-tissue sarcoma was increased, but not significantly (4 deaths; standardized mortality ratio [SMR], 338; 95 percent confidence interval, 92 to 865). In the subcohort of 1520 workers with greater than or equal to 1 year of exposure and greater than or equal to 20 years of latency, however, mortality was significantly increased for soft-tissue sarcoma (3 deaths; SMR, 922; 95 percent confidence interval, 190 to 2695) and for cancers of the respiratory system (SMR, 142; 95 percent confidence interval, 103 to 192). Mortality from all cancers combined was slightly but significantly elevated in the overall cohort (SMR, 115; 95 percent confidence interval, 102 to 130) and was higher in the subcohort with greater than or equal to 1 year of exposure and greater than or equal to 20 years of latency (SMR, 146; 95 percent confidence interval, 121 to 176). CONCLUSIONS: This study of mortality among workers with occupational exposure to TCDD does not confirm the high relative risks reported for many cancers in previous studies. Conclusions about an increase in the risk of soft-tissue sarcoma are limited by small numbers and misclassification on death certificates. Excess mortality from all cancers combined, cancers of the respiratory tract, and soft-tissue sarcoma may result from exposure to TCDD, although we cannot exclude the possible contribution of factors such as smoking and occupational exposure to other chemicals.

Fatal abuse of nitrous oxide in the workplace.

Abuse of nitrous oxide (N2O) while on the job caused at least 11 deaths in 1984 to 1987, as found in investigations by the Occupational Safety and Health Administration and in reports to the Consumer Product Safety Commission. Although nitrous oxide has had a reputation as a "clean and safe" analgesic and anesthetic, the possibility of asphyxiation by inhalation is not widely recognized, and there are no requirements for warning labels on nonmedical sources of N2O. The 11 deaths involved recreational inhalation of N2O by young male employees from tanks or cylinders normally used for legitimate business purposes. In six cases, the victims worked in food serving establishments and inhaled N2O that was used to power whipped cream dispensers. Commercial users of N2O, particularly in the restaurant industry, should be aware of this hazard. Warning labels for N2O sources and tighter control over supplies are warranted.

Concentration-dependent association of delta5-3-ketosteroid isomerase of Pseudomonas testosteroni.

Gel chromatography and ultracentrifugation studies show that delta5-3-ketosteroid isomerase of Pseudomonas testosteroni a dimer with a molecular weight of 26,800 at concentrations below 1 mg per ml, undergoes reversible, concentration-dependent association at higher enzyme concentrations. In the concentration range between 0.04 and 15.6 mg per ml, apparent molecular radii of 23 A to 36 A and molecular weights of 26,000 to 69,000 were observed. The latter value represents the weight average molecular weight of two or more ploymerization species in rapid equilibrium, rather than a discrete polymeric form of the enzyme. The isomerase dimer has been found to be unusually stable to dissociation upon dilution, even at concentrations in the nanogram per ml range. Evidence is presented which suggests that the enzyme is present as a dimer in P. testosteroni cells and that this is a catalytically active species. The isomerase monomer has been obtained and its molecular weight studied by gel electrophoresis in the presence of sodium dodecyl sulfate. A new determination of the extinction coefficient of the isomerase gives the value of 0.336 for the absorbance at 280 nm in a 1-cm light path of a solution containing 1 mg of the isomerase per ml.