days per year, an employer is required to provide a medical surveillance program that includes blood-lead sampling and medical examinations. OSHA also requires that any employee who has a BLL of 60 μg/dL or higher or three consecutive BLLs averaging 50 μg/dL or higher be removed from work that involves lead exposure. The employee may resume work that entails lead exposure only after two BLLs are under 40 μg/dL. The OSHA standard assumes that a population of workers exposed at the PEL of 50 μg/m3 will have an average BLL of 40 μg/dL or lower. It allows workers to have BLLs of up to 40 μg/dL for a working lifetime of 40 years. For workers who wish to plan pregnancies, OSHA recommends a BLL of under 30 μg/dL.
The NIOSH (1978) and ACGIH (2001a, b) guidelines are designed similarly to maintain BLLs below a threshold. NIOSH’s recommended exposure limit of 50 μg/m3 was established in 1978 and was aimed at maintaining the BLL below 60 μg/dL. ACGIH established a biological exposure index (BEI®) in 1995 of 30 μg/dL, and its threshold limit value (TLV®) of 50 μg/m3 was intended to maintain workers’ BLLs below the BEI.
Exposure standards and guidelines for protecting the general public from lead in ambient air, drinking water, soil, and consumer products have been established by such agencies as the US Environmental Protection Agency (EPA), the Agency for Toxic Substances and Disease Registry, the Centers for Disease Control and Prevention, the National Toxicology Program (NTP), and the US Food and Drug Administration. The standard for lead in air is undergoing review by EPA. Lead is one of several criteria pollutants for which EPA has established National Ambient Air Quality Standards (NAAQSs). In February 2012, EPA released an Integrated Science Assessment for Lead (Second External Review Draft), which indicates that the NAAQS for lead will probably be reduced (EPA 2012). In June 2012, the NTP completed an evaluation of the scientific evidence on the potential health effects of low-level lead exposure and concluded that “there is sufficient evidence that [BLLs] <10 μg/dL and <5 μg/dL are associated with adverse health effects in children and adults” (NTP 2012).
Because changes in environmental and occupational guidelines could affect the use of lead by the Department of Defense (DOD), the department asked the National Research Council to conduct a study of potential occupational health risks posed by exposure to lead. Of particular interest was lead exposure on small-arms firing ranges, especially exposure of range workers, who experience it recurrently. In response, the National Research Council convened the Committee on Potential Health Risks from Recurrent Lead Exposure of DOD Firing Range Personnel.
Members of the committee were selected for their expertise in general toxicology, inhalation toxicology, neurotoxicology, reproductive and developmental toxicology, immunotoxicology, toxicokinetics, epidemiology, industrial