Recommendation to OSHA Regarding Blood Lead Levels
Blood Lead Task Force Proposal to the ACOEM Board of Directors
Lead poisoning causes adverse health effects in humans in a dose-dependent fashion. Although these adverse health effects have been recognized since antiquity, more recent biochemical and physiologic studies have clearly demonstrated the direct correlation of whole blood lead levels (BLL) and the development of significant neurological, biochemical, renal, reproductive, and cardiovascular effects, among others. While some of these adverse effects are much more serious in infants and children (e.g., the developing nervous systems), it has become clear that adults are not resistant to adverse effects, and that the current Occupational Safety and Health Administration (OSHA) lead standard which allows continued exposure until BLL exceeds 50 or 60 mcg/dL is inadequate to protect the health of the American worker.
The U.S. Department of Health and Human Services (DHHS) recognizes that elevated BLLs in adults can damage the nervous, hematologic, reproductive, renal, cardiovascular, and gastrointestinal systems, and that the overwhelming majority of these cases are workplace-related. The geometric mean BLL of all adults in the United States is <3 µg/dL; therefore, DHHS recommends that BLLs among all adults be reduced to <25 µg/dL.1
The current OSHA standard was adopted in the 1970s, based on now-outdated >40-year-old science, when the geometric mean BLL values in the United States were 12.8 mcg/dL, and the “normal” BLL was considered to be <25 mcg/dL. The removal of lead from gasoline, paints, and solder in food cans, as well as instituting other public health measures, has greatly reduced the average BLLs to the present geometric mean of 1.45 mcg/dL. Recognition of the particular sensitivity of the developing brain to lead prompted the U.S. Centers for Disease Control and Prevention (CDC) in 1997 to change its childhood lead poisoning surveillance guidelines to consider a normal BLL to be <9mcg/dL.1 More recently, published studies have demonstrated decrements in cognitive scores in populations of children when BLL averaged >5 mcg/dL, and in adults with BLL >10 mcg/dL.
Therefore, the American College of Occupational and Environmental Medicine (ACOEM) is urging all employers utilizing lead in the workplace, as well as physicians caring for the health of U.S. workers, to adopt the Recommendations for Medical Management of Adult Lead Exposure” published by an expert panel in 2007.2 These provisions call for medical removal when BLL exceeds 20 mcg/dL on any two consecutive blood tests or any single value exceeding 30 mcg/dL. While the current OSHA standard applies only to those workers exposed at the OSHA action level of airborne lead dust ≥30 μg/m3 as an 8-hour time-weighted average, ACOEM believes that this standard should be applied to all lead-exposed workers who have the potential to be exposed by lead ingestion, even in the absence of documented elevations in air lead levels. In addition, ACOEM urges OSHA to update its lead standard in order to better protect American workers and to align itself with the overwhelming scientific evidence of adverse health effects in adults with BLLs well below the OSHA limits.3 In keeping with the scientific evidence, ACOEM recommends that OSHA lower the medical removal BLL as outlined above.
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1CDC. NIOSH Safety and Health Topic: Adult Blood Lead Epidemiology and Surveillance (ABLES). www.cdc.gov/niosh/topics/ABLES/ables-description.html.
2Kosnett MJ, Wedeen RP, Rothenberg SJ, et al. Recommendations for medical management of adult lead exposure. Environ Health Perspect. 2007;115(3):463-71.
3California Department of Public Health, Occupational Lead Poisoning Prevention Program (OLPPP). Medical Guidelines for the Lead-Exposed Worker. May 2009. www.cdph.ca.gov/programs/olppp/Documents/medgdln.pdf.
Acknowledgements
This document was developed by the ACOEM Task Force on Blood Lead, Michael G. Holland, MD, FACOEM, chair. It was peer-reviewed by the ACOEM Toxicology Committee and the Council of Scientific Advisors. It was approved by the ACOEM Board of Directors on January 23, 2010.
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