Analysis of biomonitoring data to assess employer compliance with OSHA's permissible exposure limits for air contaminants.

BACKGROUND: The Occupational Safety and Health Administration (OSHA) regulates exposures to hazardous chemicals in workplace air. When contemporaneous exposure measurements are unavailable, retrospective analysis of biomarkers could provide valuable information about workers' exposures. METHODS: Single-compartment pharmacokinetic (PK) models were created to relate the concentration of a chemical in the air to the concentration of the chemical or its metabolite in workers' blood or urine. OSHA utilized the PK models in investigations of three fatal incidents in which workers were exposed to nickel carbonyl, methyl bromide, or styrene. To obtain the minimum plausible estimate of each exposure, OSHA used conservative assumptions about parameters such as workers' inhalation rates, baseline levels of biomarker, and chemicals' volumes of distribution. RESULTS: OSHA analyzed a worker's urinary nickel concentration and concluded that his 8-h time-weighted average exposure to nickel carbonyl was at least 0.06 mg/m3 . Analysis of a worker's postexposure, premortem blood bromide level revealed that his exposure to methyl bromide was at least 181 mg/m3 . Post-mortem blood styrene measurements suggested that a third worker's exposure to styrene was at least 625 mg/m3 . These exposures exceeded OSHA's permissible exposure limits of 0.007 mg/m3 for nickel carbonyl, 80 mg/m3 for methyl bromide, and 426 mg/m3 for styrene. OSHA successfully cited the three employers for violations of chemical exposure limits. CONCLUSIONS: Analysis of biomarkers via PK modeling enables retrospective evaluations of workers' acute exposures to hazardous chemicals. These techniques are useful to occupational regulators who assess employer compliance with mandatory exposure limits.

An outbreak of work-related asthma and silicosis at a US countertop manufacturing and fabrication facility.

BACKGROUND: Outbreaks of severe silicosis have affected workers who fabricate artificial stone countertops. Work-related asthma (WRA) has not been a prominent feature of those prior outbreaks. METHODS: This report describes an outbreak of WRA and silicosis at a facility that manufactures and fabricates chemical-resistant countertops comprised of sand, epoxy resin, and phthalic anhydride (PA), a known respiratory sensitizer. The multi-disciplinary investigation included clinical examinations of workers, an industrial hygiene survey with qualitative and quantitative exposure assessments, and a cross-sectional questionnaire. RESULTS: Engineering controls and personal protective equipment were inadequate. Some workers were exposed to PA or silica above permissible exposure limits established by the Occupational Safety and Health Administration (OSHA). Clinical and epidemiologic investigations identified 16 workers with confirmed or suspected WRA. Two years later, after OSHA began to enforce its new silica standards, 12 workers received medical surveillance for silicosis. Of these 12 workers, four (33.3%) were diagnosed with silicosis based on abnormal chest computed tomography examinations. CONCLUSIONS: Artificial stone countertop workers can develop asthma or silicosis. Risk of asthma may be highest in workers exposed to asthmagens such as PA and epoxy resins while manufacturing the artificial stone material.

Assessment of Methylene Chloride-Related Fatalities in the United States, 1980-2018.

Importance: Methylene chloride is a halogenated organic solvent widely used in paint strippers, cleaners, adhesives, and sealants. Despite label warnings and occupational standards, methylene chloride-related fatalities continue to occur in the United States. Objective: To identify and analyze methylene chloride-related fatalities in the US. Design, Setting, and Participants: For this case series, we conducted systematic searches of sources, including PubMed and government databases, for unintentional fatalities in the US that were associated with exposure to methylene chloride or products containing methylene chloride between 1980 and 2018. We reviewed all available information, including inspection reports, autopsy reports, and medical records; data analyses were conducted from August 2018 to August 2020. Cases were categorized as those occurring in the home (consumer deaths) or at work (occupational deaths). Exposures: Methylene chloride or products containing methylene chloride. Main Outcomes and Measures: To determine characteristics of the methylene chloride-related fatalities, we recorded demographic information; the setting; circumstances, including information on safety measures used, if available; and products used. Where medical records were available, we recorded toxicology results and autopsy findings. We also obtained data about nonfatal methylene chloride cases from the American Association of Poison Control Centers. Results: From 1980 to 2018, 85 methylene chloride-related fatalities were identified in the US, including 74 (87%) in occupational settings; of those who died, 75 (94%) were men, and for the 70 cases with available information, the median (interquartile range) age of the decedents was 31 (24-46) years. Paint strippers were the most common products involved in methylene chloride-related fatalities (n = 60). The proportion of occupational fatalities related to paint stripping increased from 22 (55%) before 2000 to 30 (88%) after 2000. Similarly, occupational fatalities associated with bathtub or paint stripping in bathrooms increased from 2 (5%) before 2000 to 21 (62%) after 2000. From 1985 to 2017, the American Association of Poison Control Centers documented 37 201 nonfatal methylene chloride cases, with a decrease in the annual number of cases starting in the late 1990s. Conclusions and Relevance: Results of this case series demonstrated that despite regulations to address the toxic effects of methylene chloride use for consumers and workers, there are continuing fatalities in the US, particularly in occupational settings. Prevention of fatalities associated with methylene chloride exposure should emphasize the use of safer substitutes, rather than hazard warnings or reliance on personal protective equipment.

Evaluation of Occupational Exposure Limits for Heat Stress in Outdoor Workers - United States, 2011-2016.

Heat stress, an environmental and occupational hazard, is associated with a spectrum of heat-related illnesses, including heat stroke, which can lead to death. CDC's National Institute for Occupational Safety and Health (NIOSH) publishes recommended occupational exposure limits for heat stress (1). These limits, which are consistent with those of the American Conference of Governmental Industrial Hygienists (ACGIH) (2), specify the maximum combination of environmental heat (measured as wet bulb globe temperature [WBGT]) and metabolic heat (i.e., workload) to which workers should be exposed. Exposure limits are lower for workers who are unacclimatized to heat, who wear work clothing that inhibits heat dissipation, and who have predisposing personal risk factors (1,2). These limits have been validated in experimental settings but not at outdoor worksites. To determine whether the NIOSH and ACGIH exposure limits are protective of workers, CDC retrospectively reviewed 25 outdoor occupational heat-related illnesses (14 fatal and 11 nonfatal) investigated by the Occupational Safety and Health Administration (OSHA) from 2011 to 2016. For each incident, OSHA assessed personal risk factors and estimated WBGT, workload, and acclimatization status. Heat stress exceeded exposure limits in all 14 fatalities and in eight of 11 nonfatal illnesses. An analysis of Heat Index data for the same 25 cases suggests that when WBGT is unavailable, a Heat Index screening threshold of 85°F (29.4°C) could identify potentially hazardous levels of workplace environmental heat. Protective measures should be implemented whenever the exposure limits are exceeded. The comprehensive heat-related illness prevention program should include an acclimatization schedule for newly hired workers and unacclimatized long-term workers (e.g., during early-season heat waves), training for workers and supervisors about symptom recognition and first aid (e.g., aggressive cooling of presumed heat stroke victims before medical professionals arrive), engineering and administrative controls to reduce heat stress, medical surveillance, and provision of fluids and shady areas for rest breaks.

Risk Factors for Heat-Related Illness in U.S. Workers: An OSHA Case Series.

OBJECTIVE: The aim of this study was to describe risk factors for heat-related illness (HRI) in U.S. workers. METHODS: We reviewed a subset of HRI enforcement investigations conducted by the Occupational Safety and Health Administration (OSHA) from 2011 through 2016. We assessed characteristics of the workers, employers, and events. We stratified cases by severity to assess whether risk factors were more prevalent in fatal HRIs. RESULTS: We analyzed 38 investigations involving 66 HRIs. Many workers had predisposing medical conditions or used predisposing medications. Comorbidities were more prevalent in workers who died. Most (73%) fatal HRIs occurred during the first week on the job. Common clinical findings in heat stroke cases included multiorgan failure, muscle breakdown, and systemic inflammation. CONCLUSION: Severe HRI is more likely when personal susceptibilities coexist with work-related and environmental risk factors. Almost all HRIs occur when employers do not adhere to preventive guidelines.

Associations between Depressive Symptoms and 30-day Hospital Readmission among Older Adults.

BACKGROUND: Hospital readmissions are common and costly. Our goal was to determine the association between depressive symptoms and readmission within 30 days following hospital discharge in older adults. METHODS: We analyzed data from a study of 789 persons aged 65 years or older admitted to a 20-bed acute care for elders (ACE) hospital unit from May 2009 to July 2011. Depressive symptoms were recorded within 24-hours of admission to the hospital unit, using the Center for Epidemiologic Studies -Depression (CES-D) Scale. The primary outcome was readmission to hospital within 30 days of discharge. RESULTS: The mean age was 77 years; 66% were female, 72% were White, and 59% were unmarried. On average, older patients reported 2.6 comorbid conditions. Sixteen percent were classified with high depressive symptoms (CES-D ≥ 16). The readmission rate within 30 days was 15%. Older patients with high depressive symptoms had more than 1.6 times the odds (OR 1.66; 95% CI: 1.01-2.74) of being readmitted within 30-days, as compared to those with low depressive symptoms (CES-D < 16), after adjustment for age, race/ethnicity, sex, marital status and comorbid conditions. CONCLUSION: High depressive symptoms increased the risk of hospital readmission within 30 days of discharge after adjusting for relevant covariates. In-hospital screening for depressive symptoms may identify older persons at risk for recurrent hospital admissions.