Current Trends Surveillance for Occupational Lead Exposure -- United States, 1987

Since 1981, four states (California, New Jersey, New York, and Texas) have implemented surveillance systems for occupational lead exposure. Although the details of these systems, each state requires any laboratory that performs blood-lead assays to report all elevated blood-lead levels (BLLs) to the state health department (SHD) (Table 1). The SHD then uses telephone follow-up (with either the physician who submitted the blood specimen or the patient) to obtain demographic information and identify possible occupational lead exposures.

This report summarizes 1987 surveillance data from these states on adults* with BLL greater than or equal to 40 ug/dL of whole blood.** A person was counted as a case-patient only once, even though some persons may have been reported several times within the year. The highest BLL reported for each person (peak BLL) was used for this report.

For 1987, 1926 adults with elevated BLLs were reported to the four SHDs; for 524 (27.2%) persons, BLL exceeded 50 ug/dL.*** Most (93%) elevated BLLs occurred in males, and most (94% (excluding New Jersey, for which specific data were not available)) were work-related.**** The age distribution was similar in the four states; the greatest proportions of persons with elevated BLLs were aged 25-34 and 35-44 years. In California and Texas, 44% and 40% of reported persons, respectively, were Hispanic; in contrast, Hispanics represent approximately 24% and 25%, respectively, of these states' populations (Bureau of the Census, unpublished data, 1988).

Elevated BLLs were most common in workers employed in industrial sectors with well-known lead hazards, such as primary and secondary lead smelting, brass foundries (both Standard Industrial Code (SIC) 33), and battery manufacturing (SIC 36) (Table 2). Less common sources included: construction (including bridge reconstruction and home rehabilitation), ceramics manufacture, plastics production, stained-glass window production, ammunition manufacture, and firing ranges (both for sport and law-enforcement training).

Case follow-up efforts vary by state, but all attempt to 1) confirm occupational lead exposure by gathering more information about work history, hobbies with possible lead exposures, symptoms, and household contacts from the affected person or the reporting source, 2) provide educational and technical information to affected workers, attending physicians, and employers, and 3) arrange onsite evaluations of the lead hazard. Follow-up procedures may entail telephone contact with all newly reported workers, telephone contact only when a threshold BLL is exceeded, or telephone contact with the initiator (physician or employer) of the blood-lead test. Educational materials may be mailed to affected workers (and their physicians) or may be distributed to all lead-exposed workers when worksite inspections are conducted.

Worksite follow-up visits, including industrial hygiene evaluations, are part of each state's program. For example, the New Jersey Department of Health conducted 54 worksite visits from October 1985 through May 1989. In New York, selected worksite industrial hygiene surveys are conducted by the SHD, which refers employers to the State Department of Labor for technical assistance. Less frequently, OSHA (either the consultation program or compliance section) may be contacted. In Texas, the SHD refers employers to either the state OSHA consultation program or to an industrial hygienist employed by the SHD. Reported by: L Rudolph, MD, N Maizlish, PhD, California Dept of Health Svcs. A Tepper, PhD, B Gerwel, MD, T Wenzl, MS, New Jersey Dept of Health. J Melius, MD, R Stone, PhD, New York State Dept of Health. J Martin, PhD, J Pichette, Texas Dept of Health. M Montopoli, MD, Univ of Illinois Occupational Health and Safety Center. Surveillance Br, Div of Surveillance, Hazard Evaluations, and Field Studies, National Institute for Occupational Safety and Health, CDC.

Editorial Note

Editorial Note: Lead poisoning, first described by Hippocrates around 370 B.C., is the oldest recognized occupational disease. The clinical and pathophysiologic effects of higher levels of lead exposure are well known, but evidence continues to emerge concerning adverse health effects at lower BLLs (2). In the occupational setting, inhalation of lead dust and fume is the primary route of absorption. Data from the National Occupational Exposure Survey conducted from 1981-1983 by the National Institute for Occupational Safety and Health (NIOSH), CDC, indicate that approximately 827,000 U.S. workers are potentially exposed***** to lead on the job (3; CDC, unpublished data, 1989). Workplace exposure has also been described as a vector for childhood and community lead exposure through contamination of work clothing and the local environment (4).

In 1979, OSHA promulgated a Standard for Occupational Exposure to Lead (1), which requires that, in workplaces where lead is used, employers must monitor for airborne contamination. When airborne lead concentrations exceed 30 ug/m3 of air (averaged over an 8-hour workshift), employers must provide an industrial hygiene program and medical surveillance (including the monitoring of BLLs). The OSHA permissible exposure limit (PEL) for lead is 50 ug/m3 for an 8-hour workshift (1). An employee with one BLL greater than or equal to 60 ug/dL or three BLLs that average greater than or equal to 50 ug/dL over a 6-month period must be moved to a job without lead exposure until the worker's BLL declines to an acceptable level (i.e., 40 ug/dL) (1). Although the OSHA Lead Standard has been in effect for greater than 10 years, the data in this report indicate that overexposures to lead continue in many industries.

Construction-related industries (SICs 16 and 17) accounted for the highest proportion (30.4%) of workers with BLLs greater than or equal to 70 ug/dL. The OSHA Lead Standard does not apply to the construction industry, for which OSHA has established a separate PEL of 200 ug/m3 and does not require medical monitoring (5). Although the construction industry has a higher PEL for lead, this level is frequently exceeded when cutting or welding torches are used on bridges coated with lead-containing paints (6,7). Lead overexposures in the construction industry should be given greater attention.

In California and Texas, the rates of elevated BLLs for Hispanics were higher than this group's relative proportion of population in those states. (Occupational disease and injury rates are higher for minority workers than for other groups, possibly because they may be employed disproportionately in shops with suboptimal controls and greater exposures (8).) Because the potential impact of occupational lead exposure as a minority health concern has not been previously addressed, in California, Spanish-language educational materials describing the hazards and control of lead in the workplace have been developed for minority workers.  Since 1987, the Wisconsin, Maryland, and Colorado SHDs have implemented similar BLL surveillance systems, and other states are considering such systems. NIOSH, in collaboration with SHDs through the Sentinel Event Notification System for Occupational Risks program, is supporting this program development effort. A key consideration for surveillance of this problem is selection of the BLL necessary for triggering a report to the SHD. Most of the states conducting surveillance of lead toxicity in adults have adopted the level recommended by CDC for nonoccupational settings (25 ug/dL) as an indicator for elevated BLLs in children (9).

To eliminate occupational lead poisoning (10), blood-lead surveillance programs, such as those described here, are crucial for identifying individual workers and workplaces with overexposure to lead. These programs enable targeting of public health, technical, and educational resources to those worksites in need of assistance.

References

1. Office of the Federal Register. Code of federal regulations:

occupational safety and health standards. Subpart Z: Toxic and hazardous substances--lead. Washington, DC: Office of the Federal Register, National Archives and Records Administration, 1985. (29 CFR Section 1910.1025).

2. McMichael AJ, Baghurst PA, Wigg NR, Vimpani GV, Robertson EF, Roberts RJ. Port Pirie Cohort Study: environmental exposure to lead and children's abilities at the age of four years. N Engl J Med 1988;319:468-75.

3. Seta JA, Sundin DS, Pedersen DH, NIOSH. National Occupational Exposure Survey: field guidelines. Vol 1. Survey manual. Cincinnati, Ohio: US Department of Health and Human Services, Public Health Service, 1988; DHHS publication no. (NIOSH)88-106.

4. Kaye WE, Novotny TE, Tucker M. New ceramics-related industry implicated in elevated blood lead levels in children. Arch Environ Health 1987;42:161-4.

5. Office of the Federal Register. Code of federal regulations: safety and health regulations for construction. Subpart J: Welding and cutting--welding, cutting, and heating in way of preservative coatings. Washington, DC: Office of the Federal Register, National Archives and Records Administration, 1988. (29 CFR Section 1926.354).

6. Pollock CA, Ibels LS. Lead intoxication in paint removal workers on the Sydney Harbour Bridge. Med J Aust 1986;145:635-9.

7. Landrigan PJ, Baker EL Jr, Himmelstein JS, Stein GF, Wedding JP, Straub WE. Exposure to lead from the Mystic River Bridge: the dilemma of deleading. N Engl J Med 1982;306:673-6.

8. US Department of Health and Human Services. Report of the Secretary's Task Force on Black and Minority Health. Washington, DC: US Department of Health and Human Services, Public Health Service, 1986.

9. CDC. Preventing lead poisoning in young children: a statement by the Centers for Disease Control. Atlanta: US Department of Health and Human Services, Public Health Service, 1985. 10. Public Health Service. Promoting health/preventing disease: objectives for the nation. Washington, DC: US Department of Health and Human Services, Public Health Service, 1980:42. *For this report, California and New York define adults as persons aged greater than or equal to 18 years; Texas uses age 15 years as the reporting threshold, and New Jersey uses age 16 years. **This threshold was chosen for this report to permit comparison of data among the four states because Texas collects data only at or above this level. ***An average BLL of 50 ug/dL based on three blood samples over a 6-month period or one sample greater than 60 ug/dL requires medical removal of employee from lead exposure without loss of wages, benefits, or seniority (Occupational Safety and Health Administration (OSHA) Lead Standard) (1). ****During follow-up interview, the affected person indicated that exposure to lead occurred at work. *****The survey defined potential exposure as 1) observation of the chemical in sufficient proximity to an employee such that one or more physical phases of the substance is likely to enter or contact the body of the worker and 2) meeting minimum duration of exposure guidelines (3).

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