Panel Finds OSHA Lead Exposure Standard Inadequate
A new report from a National Research Council committee says the current standard sets limits that do not protect personnel working on military firing ranges from harmful exposures.
A new National Research Council report concludes the current OSHA general industry standard for lead exposure, 29 CFR 1910.1025, is not sufficiently protective, given that blood lead levels below what the 34-year-old standard regards as safe are known to cause health problems.
The standard sets an action level of 30 micrograms per cubic meter of air (µg/m3) as an eight-hour TWA and requires medical surveillance of workers exposed above that level for more than 30 days per year, and an employee with a blood lead level of 60 µg/dL of higher of three consecutive blood lead levels average 50 or higher must be removed from work involving lead exposure. But the report's summary points out that the U.S. National Toxicology Program and EPA have identified health effects below 10 µg/dL, and in some cases as low as 5 µg/dL. The report says adverse kidney effects occur with blood lead levels of 8-12 µg/dL, while adverse cardiovascular effects are seen at BLLs below 10 µg/dL.
Hearing loss, increased blood pressure, impaired balance, and other adverse effects also occur below 30 µg/dL, according to the report, which cites a model showing that an average worker who is exposed at the OSHA action level for one year would have a BLL of about 30 µg/dL as a result.
The Department of Defense asked the National Research Council to evaluate employees' potential health risks from recurring exposures at firing ranges. "Data collected for the last 5 years show that the OSHA PEL for lead of 50 µg/m3 was frequently exceeded on Army, Navy, and Air Force firing ranges, in some cases by several orders of magnitude. [Blood lead level] data on firing-range personnel were not available from either the Army or the Navy, but the Air Force reported that BLLs of its firing range personnel were all under 40 µg/dL," the summary states.
Based on its review of the epidemiological and toxicologic data, the committee concluded "there is overwhelming evidence that the OSHA standard provides inadequate protection for DOD firing-range personnel and for any other worker populations covered by the general industry standard. Specifically, the premise that maintaining BLLS under 40 µg/dL for a working lifetime will protect workers adequately is not valid; by inference, the OSHA PEL and action level are also inadequate for protecting firing-range workers," according to the report.
It notes that the American College of Occupational and Environmental Medicine has recommended medical removal of workers with BLLs above 20 µg/dL.
The committee recommended that DoD consider switching from lead bullets to nylon-clad, copper-jacketed, zinc-based, or other alternative ammunition types, though these would be more expensive. The department also should improve ranges' design and ventilation, should keep them cleaner, and should consider requiring exposed workers to use a mixture of isostearamidopropyl morpholine lactate and citric acid, applied with a textured absorbent material, to decontaminate their hands after exposures.
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