Methemoglobinemia resulting from exposure in a confined space: Exothermic self-polymerization of 4,4'-methylene diphenyl diisocyanate (MDI) material.

A worker attempting to remove solidified material inside a confined space (storage tank) suffered severe methemoglobinemia and almost died. The tank contained liquid 4,4'-methylene diphenyl diisocyanate monomer that had solidified after an equipment power failure caused excessive heating. Wearing a full-face elastomeric air-purifying respirator and Tyvek® coveralls, the worker used pneumatic air hammers to break up the solid material. After two tank entries totaling slightly less than one hour, the worker complained of headache and dizziness and within two hours of exiting the tank, he was admitted to the hospital in severe respiratory distress. During his eight-week hospital course, he suffered a cardiac arrest among other complications. An investigation into the cause of the worker's illness used onsite gas chromatography-mass spectrometry which identified aniline and p-toluidine vapor within the tank, attributable to overheating that led to formation of the solid material. Both are well-known causes of methemoglobinemia, and had the initial characterization of the confined space atmosphere adequately identified the hazards present appropriate engineering controls and personal protective equipment could have allowed the tank entrant to work safely in the space.

Case cluster of pneumoconiosis at a coal slag processing facility.

BACKGROUND: During an inspection by the Occupational Safety and Health Administration (OSHA) of a small coal slag processing plant with 12 current workers, four cases of pneumoconiosis were identified among former workers. METHODS: The OSHA investigation consisted of industrial hygiene sampling, a review of medical records, and case interviews. RESULTS: Some personal sampling measurements exceeded the OSHA Permissible Exposure Limit (PEL) for total dust exposures of 15 mg/m(3), and the measured respirable silica exposure of 0.043 mg/m(3), although below OSHA's current PEL for respirable dust containing silica, was above the American Conference of Governmental Industrial Hygienists' Threshold Limit Value (TLV). Chest x-rays for all four workers identified small opacities consistent with pneumoconiosis. CONCLUSION: This is the first known report of lung disease in workers processing coal slag and raises concerns for workers exposed to coal slag dust.

Under-recording of work-related injuries and illnesses: An OSHA priority.

INTRODUCTION: A 2009 Government Accounting Office (GAO) report, along with numerous published studies, documented that many workplace injuries are not recorded on employers' recordkeeping logs required by the Occupational Safety and Health Administration (OSHA) and consequently are under-reported to the Bureau of Labor Statistics (BLS), resulting in a substantial undercount of occupational injuries in the United States. METHODS: OSHA conducted a Recordkeeping National Emphasis Program (NEP) from 2009 to 2012 to identify the extent and causes of unrecorded and incorrectly recorded occupational injuries and illnesses. RESULTS: OSHA found recordkeeping violations in close to half of all facilities inspected. Employee interviews identified workers' fear of reprisal and employer disciplinary programs as the most important causes of under-reporting. Subsequent inspections in the poultry industry identified employer medical management policies that fostered both under-reporting and under-recording of workplace injuries and illnesses. CONCLUSIONS: OSHA corroborated previous research findings and identified onsite medical units as a potential new cause of both under-reporting and under-recording. Research is needed to better characterize and eliminate obstacles to the compilation of accurate occupational injury and illness data. PRACTICAL APPLICATIONS: Occupational health professionals who work with high hazard industries where low injury rates are being recorded may wish to scrutinize recordkeeping practices carefully. This work suggests that, although many high-risk establishments manage recordkeeping with integrity, the lower the reported injury rate, the greater the likelihood of under-recording and under-reporting of work-related injuries and illnesses.

Paranitroanaline poisoning: a failure in basic prevention?

The Occupational Medicine Forum is prepared by the ACOEM Occupational and Environmental Medical Practice Committee and does not necessarily represent an official ACOEM position. The Forum is intended for health professionals and is not intended to provide medical or legal advice, including illness prevention, diagnosis or treatment, or regulatory compliance. Such advice should be obtained directly from a physician and/or attorney.