Occupational Exposure to BPA

You may have seen water bottles labeled “BPA Free” or heard that certain foods contain BPA (bisphenol A).
In the news over the past several years, BPA is weakly estrogenic; that is, it may mimic some of the hormone-like effects of estrogen.
It is used primarily in making polycarbonate plastic some epoxy resins, and certain specialty waxes
The general population is exposed to BPA mainly through diet. Trace levels of BPA may be present in food or beverages in contact with polycarbonate containers or epoxy resins coatings on the inside of cans.
As a result, BPA has been detected in the urine of over 92% of the general population. But what about the exposures of people who work with BPA?
The few studies that have measured worker exposure to BPA have focused mainly on cashiers handling point-of-sale thermal receipt paper coated with BPA and workers in Chinese factories. No published data were available on the BPA exposure of workers in U.S. factories.

NIOSH BPA Exposure Study

The National Institute for Occupational Safety and Health undertook a study in 2013–2014 to measure BPA exposure in U.S. manufacturing workers.
The study included six companies that either made BPA, BPA-based resins, or made and used BPA-filled waxes. A total of 78 workers participated.
Over two consecutive work days, each participant provided seven urine samples, and BPA was measured in the samples.
On average, workers in the NIOSH study had BPA levels in their urine approximately 70 times higher than adults in the U.S. general population (based on data from the 2013–2014 National Health and Nutrition Examination Survey, a representative sample of the U.S. general population).

Unlike the general population, these workers handled raw BPA, often in large quantities. And unlike the general population, workers in the study were exposed to BPA mainly by inhalation and dermal absorption.
NIOSH investigators found that work tasks such as handling bags or sacks of BPA and taking process or bulk samples containing BPA for quality control testing were associated with increased urinary BPA levels in the workers.
Workers who handled a resin product where only trace levels of BPA remained had the lowest urinary BPA levels.
Among the highest exposed workers were those who worked with molten casting wax containing BPA.

Minimizing Exposure

Neither NIOSH, OSHA, nor the American Conference of Governmental Industrial Hygienists have occupational exposure limits for BPA.
Consequently, NIOSH encourages companies to review work practices for ways to minimize worker exposure to BPA by following the hierarchy of controls.
Exposure reduction steps could include:

• Eliminating BPA or substituting other chemicals for BPA. In applications where BPA is an essential component of a material, such as in polycarbonate plastic, substitution may not be an option
• Containing BPA dust and vapor emissions with either full enclosures or local exhaust ventilation
• Minimizing the time workers spend in BPA production areas
• Cleaning surfaces in production areas, offices, and lunch rooms regularly to remove BPA residues
• Using personal protective equipment as a last resort and assuring that PPE is properly fitted, worn, maintained, and cleaned. PPE may include respirators, chemically-resistant gloves and suits, and eye and face protection
• Implementing a sampling program for BPA to evaluate the efficacy of controls and surface decontamination efforts.

The NIOSH study contributes new information on worker exposure to BPA in one U.S. sector—manufacturing. This is only one step, however, on the path to assessing the health and safety of working with BPA.
Other research questions arising from the study include: Is BPA affecting the health of exposed workers? How does the body handle BPA after inhalation and dermal exposure? Is BPA stored in the body after repeated long-term exposure to BPA at occupational levels? In industrial processes where BPA is heated, does BPA vaporize? Do family members of workers have “take-home” exposure to BPA?
NIOSH welcomes your thoughts on this study and suggestions for future research.

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About the author: Cynthia Hines, MS, CIH, is a senior research industrial hygienist in the NIOSH Division of Surveillance, Hazard Evaluations, and Field Studies.