For years, manufacturers have used the industrial chemical BPA, or bisphenol A, to make polycarbonate plastic, epoxy resins, and other specialty materials. Although the effects of BPA on people remain unclear, health concerns about the chemical have arisen because it weakly mimics the hormone estrogen.
Previous studies have shown that nearly all people have BPA in their urine, likely from their diet. For workers who handle the chemical, the level of exposure may be even higher.
The United States currently has no occupational exposure limits for BPA. After a study in China reported reproductive health effects in factory workers who handled BPA, investigators at the National Institute for Occupational Safety and Health began studying BPA exposure among U.S. manufacturing workers.
Now, a NIOSH study published in the Annals of Work Exposures and Health and the Journal of Occupational and Environmental Hygiene is the first to report urine, air, and skin exposure levels to BPA among these workers.
The study found urinary BPA levels comparable to the Chinese workers. These levels were 70 times higher, on average, in study participants than in U.S. adults surveyed by the Centers for Disease Control and Prevention. In addition, nearly all air and hand wipe samples tested had detectable levels of BPA.
BPA levels also varied by job. In an unexpected finding, the highest exposed job was working with molten BPA-filled wax. Although, these workers did not handle raw BPA, the chemical may have vaporized from the heated wax, the investigators said.
The lowest exposed job involved making a product in which only trace amounts of BPA remain in the finished material.
Six companies using large quantities of BPA and 78 manufacturing workers participated in the study. The companies included BPA producers and other manufacturers of BPA-containing materials, including resin and wax.
The highest exposed job was working with molten BPA-filled wax.
They found that BPA levels in eating and office areas were lower than in production areas.
In addition, investigators found that BPA levels in the studied workers could not be explained by diet alone and likely occurred by inhaling BPA and touching surfaces and objects with chemical residues.
These and similar findings from other studies show the importance of additional research into BPA exposure among U.S. workers.
To reduce work-related exposure to BPA, NIOSH recommends several approaches:
- Eliminating BPA or, if possible, substituting other chemicals for BPA.
- Containing BPA dust and vapor emissions with engineering controls such as full enclosures or local exhaust ventilation.
- Minimizing time spent in BPA-production areas.
- Cleaning surfaces regularly to remove BPA residues.
- Implementing a sampling program for BPA to evaluate the efficacy of controls.
- Using personal protective equipment, as a last resort.