European Agency Makes Recommendations Regarding OELs for Chloroprene, GMA
New scientific reports published by the European Chemicals Agency include ECHA’s recommendations regarding occupational exposure limits for the substances 2-chloro-1,3-butadiene, or chloroprene, and 2,3-epoxypropyl methacrylate, which is also known as glycidyl methacrylate or GMA. According to the agency, these substances are classified under carcinogen category 1B, which means that they are presumed to have carcinogenic potential for humans based on evidence in animals. ECHA was tasked by the European Commission to evaluate exposure to these substances to assess the option of airborne OELs, other limit values such as biological limit values and biological guidance values, and notations.
Chloroprene is used in the manufacture of a number of products, including adhesives and automotive or industrial parts. NIOSH, which describes chloroprene as a potential occupational carcinogen, lists symptoms of exposure to the substance including irritation of the eyes, skin, or respiratory system; anxiety or irritability; dermatitis; alopecia; or reproductive effects. ECHA’s evaluation (PDF) found that there was not sufficient information available to identify a threshold mode of action for the carcinogenic effects of chloroprene, which the report explains makes it not possible to derive a health-based OEL. Therefore, ECHA does not propose any limit values or notations for chloroprene. However, the report includes a table illustrating the cancer exposure-risk relationship (ERR) for the substance, which was derived from animal data. The ERR assumes that a worker is exposed to chloroprene for eight hours per day, five days per week, over a 40-year working life period. For example, exposure to chloroprene at a 0.014 ppm (or 0.052 mg/m3) concentration in air would result in excess lifetime cancer risk of four cases per 100,000 exposed, according to the ERR.
GMA is primarily used in the production of epoxy polymers and vinyl and acrylic resins, and ECHA’s report (PDF) says that it is “expected to be readily absorbed following oral, dermal and inhalation exposure.” The agency proposes a skin notation for GMA because it is “acutely toxic” when it comes into contact with skin, which the report explains indicates “systemic uptake via the dermal route.” ECHA also proposes a skin sensitization notation for GMA. As with chloroprene, the agency was unable to identify a threshold mode of action for the carcinogenic effects of GMA, so the report does not propose any health-based OELs. The report includes one recommendation regarding limit values: when a binding OEL is established for GMA, ECHA recommends that the 15-minute short-term exposure limit be set not more than five times higher than the OEL value.
“This will ensure the protection of the workers, from local irritation occurring at short exposure durations,” ECHA explains.
Stakeholders are invited to comment on ECHA’s OEL proposals until March 28. More information is available on the agency’s website.