The Journal of Occupational and Environmental Hygiene, a peer-reviewed journal dedicated to research on workplace conditions and safety, recently published an independent study sponsored by the Battery Council International (BCI) that found that the airborne lead particle size observed in lead battery manufacturing and secondary smelter facilities significantly changes previously held assumptions about lead absorption rates.
While other studies have been conducted to investigate occupational lead exposure, the new study is the first modern study to analyse actual workplace lead-in-air data collected in the U.S. It finds that the lead in air at lead battery manufacturing facilities (BMFs) and secondary smelter facilities (SSFs) has a larger particle size than was previously assumed, which could dramatically reduce the rate at which workers absorb lead into the body. As prior studies have shown, the size of the airborne lead particle plays a significant role in absorption rates because particle size determines where and how much airborne lead is deposited into the respiratory tract and stomach and then subsequently is absorbed into the body. The study posits that this means that prior modelling efforts likely over-estimate the rate at which airborne lead would be absorbed by workers’ bodies.
The study is based on monitoring at nine BMFs and five SSFs across the country. The data showed the presence of predominantly larger-sized particles in the work environments evaluated, with average mass median aerodynamic diameters (MMADs) ranging from 21 to 32 µm at BMFs and from 15 to 25 µm at SSF. Data concluded that the presence of submicron range lead mass measured at these facilities was generally small, from 0.8-3.3 percent at BMFs and 0.44-6.1 percent at SSFs.
“Data collection of this kind is crucial to properly setting occupational exposure limits for lead,” said Mark O. Thorsby, BCI’s Executive Vice President. “This report introduces a new variable to consider when determining safety standards at battery manufacturing facilities and other facilities dealing with lead.”
Access the full report in Volume 14, Issue 8 of the Journal of Occupational and Environmental Hygiene.