Lead Poisoning in Bridge Demolition Workers -- Massachusetts
In March 1988, lead poisoning was diagnosed in five of nine workers employed by a contractor to demolish a bridge spanning a river in western Massachusetts. A subsequent investigation by the Occupational Safety and Health Administration (OSHA) determined that from November 1987 through early March 1988 four of the affected workers had used acetylene torches to cut apart large sections of the bridge; the fifth had cut these sections into smaller pieces on a barge moored below the bridge.
In March 1988, two of the five workers involved in the cutting process sought medical advice: one had headaches and myalgia, and the other had nausea and arthralgia. Blood-lead levels (BLL) (tested on the basis of occupational history) were 78 and 67 ug/dL*, respectively (Table 1, page 693). The three other workers involved in the cutting process were then evaluated; their reported symptoms included joint stiffness, abdominal pain, irritability, and memory loss. BLLs in these workers were 58, 74, and 160 ug/dL. The highest BLL, 160 ug/dL, occurred in the worker assigned to the barge. Because the four remaining crew members had not worked in areas where they would have been exposed to lead fumes, they were not tested.
Four of the five affected workers were treated with chelation therapy (calcium ethylenediaminetetraacetic acid (EDTA)). Each worker excreted substantial amounts of lead and experienced a decline in symptoms. The fifth worker, who had a BLL of 58 ug/dL, demonstrated elevated lead excretion when given a test dose of EDTA. However, because he had become asymptomatic and had no evidence of organ damage, he was not treated with chelation therapy.
The OSHA investigation determined that paint covering the bridge contained 30% lead (by weight). Respirators available to the workers were not always equipped with cartridges that protected against lead fumes. The workers were not trained to OSHA standards in respirator use and wore the respirators infrequently. In addition, the employer had not provided clean work clothing or handwashing and eating facilities for the workers. OSHA cited the contractor for violating several regulations governing proper use of respirators. Reported by: J Himmelstein, MD, M Wolfson, MD, G Pransky, MD, Univ of Massachusetts Medical Center, Worcester; D Morse, MD, MassWEST Occupational Health Svcs, Holyoke; A Ross, MD, Farron Health Center, Turners Falls, Massachusetts. J Gill, Occupational Safety and Health Administration. Surveillance Br, Div of Surveillance, Hazard Evaluations, and Field Studies, National Institute for Occupational Safety and Health, CDC.
Editorial Note: Based on findings from the 1981-1983 National Occupational Exposure Survey, an estimated 827,650 U.S. workers have potential work-related exposure to lead (excluding leaded gasoline) (CDC, unpublished data). In the workplace, the respiratory tract is the major route of lead absorption. Clinical manifestations of occupational lead poisoning, which usually occur when BLLs exceed 40 ug/dL, can vary greatly in severity and include abdominal pain, anorexia, fatigue,arthralgia, headaches, irritability, depression, impotence, anemia, and hyperuricemia (2). Encephalopathy, peripheral neuropathies, and impaired renal function have been reported, but are infrequently associated with occupational exposure (2).
Lead poisoning may occur when workers and employers fail to recognize the presence of lead or fail to adhere to accepted safety guidelines. Recent reviews of workers' compensation data and laboratory-based lead registries indicate that workers at highest risk for lead toxicity include persons who work in lead smelters, storage battery-manufacturing plants, plastic-compounding factories, and nonferrous foundries (3,4; California Department of Health Services, unpublished data, 1987). Construction or demolition work that involves cutting through lead-coated metal structures, a process that generates high concentrations of lead fumes, can also present substantial risk for lead toxicity. Lead poisoning has been described in workers who repair and disassemble ships (5) and roofs (6,7), dismantle elevated subway lines (8,9), and demolish and strip paint from bridges (10-13).
Construction workers in the United States are excluded from regulation under the OSHA Lead Standard (1). However, other OSHA regulations governing the construction industry require respiratory protection for workers who use torches to cut through toxic preservative coatings, such as lead-containing paints (14), and mandate engineering controls or respiratory protection for workers exposed to airborne lead at concentrations greater than 200 ug/m3 (15).
As bridges in the United States age, they will require demolition or rebuilding. Construction workers engaged in these processes are at risk for hazardous lead exposure. Proper preventive measures, including engineering controls and appropriate use of respirators, should be carefully implemented. Physicians caring for construction workers should take thorough occupational histories and be aware that workers engaged in bridge demolition work may be at increased risk for occupational lead poisoning.
occupational safety and health standards. Subpart Z: Toxic and hazardous substances--lead. Washington, DC: Office of the Federal Register, National Archives and Records Administration, 1988. (29 CFR Section 1910.1025).
2. Cullen MR, Robins JM, Eskenazi B. Adult inorganic lead intoxication: presentation of 31 new cases and a review of recent advances in the literature. Medicine 1983;62:221-47.
3. Seligman PJ, Halperin WE, Mullan RJ, Frazier TM. Occupational lead poisoning in Ohio: surveillance using workers' compensation data. Am J Public Health 1986;76:1299-1302.
4. Wenzl TB, Conrad F, Tarlau ES, Siwinski G. Heavy metal hazard surveillance. Presented at the American Industrial Hygiene Conference, San Francisco, California, May 16, 1988.
5. Zenz C. Occupational medicine: principles and practical applications. 2nd ed. Chicago: Year Book Medical Publishers, 1988:550. 6. Susbielle G, Guyotjeannin C. Risques particuliers a certains postes de couvreurs. Arch Mal Professionnelles 1970;31:246-7.
7. Campbell BC, Baird AW. Lead poisoning in a group of demolition workers. Br J Ind Med 1977;34:298-304.
8. Feldman RG, Lewis J, Cashins R. Subacute effects of lead-oxidefumes in demolition workers (Letter). Lancet 1977;1:89-90.
9. Fischbein A, Daum SM, Davidow B, et al. Lead hazard among ironworkers: dismantling lead-painted elevated subway line in New York City. N Y State J Med 1978;78:1250-9. 10. Zimmer FE. Lead poisoning in scrap-metal workers. JAMA 1961;175:238-40. References 11-15 may be obtained from the Surveillance Branch, Division of Surveillance, Hazard Evaluations, and Field Studies, NIOSH, CDC, 4676 Columbia Parkway, Mailstop R-10, Cincinnati, OH 45226. *OSHA regulations state that an employee with confirmed BLL greater than 60 ug divided by L must be removed from lead exposure; similarly, an employee whose average BLL (measured on three occasions within 6 months) exceeds 50 ug divided by L must be removed from lead exposure (1).
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