Evaluation and updates to the Leggett model for pharmacokinetic modeling of exposure to lead in the workplace – Part I adjustments to the adult systemic model

ACOEM Position Statement

“…32 Recently, two independently developed biokinetic models, the Leggett+ model and the DoD-O'Flaherty model, have been published to assist regulators in the identification of airborne occupational exposure limits (ie, permissible exposure limits) for lead that would maintain workers' blood lead concentration below various thresholds. The Leggett+ model, 33,34 published by the California Office of Environmental Health Hazard Evaluation at the request of the California Department of Health, estimated various concentrations of lead in workplace air inhaled by workers without respiratory protection that could result in specified lead concentrations in workers' blood. Assuming 40 years of working life exposure beginning at age 25 years and a background blood lead concentration of 1.5 μg/dL, the model predicted that an 8-hour TWA PEL of 2.1 μg/m 3 would result in a 95th percentile BLL of 10 μg/dL.…”