The sentinel cases of the debilitating lung disease bronchiolitis obliterans were among workers at a microwave popcorn facility. It wasn’t too long before NIOSH researchers suspected the illnesses were related to workers’ exposure to the butter flavoring agent used in the plant. The compounds are typically a mixture of volatile organic compounds (VOC), many of which can irritate severely the skin, eyes and respiratory tract. Diacetyl, a 4-carbon alpha-diketone, was one of the VOCs identified in the microwave popcorn plant environment. Diacetyl has come to serve as the catch-all name for the butter-flavoring agents, although NIOSH researchers noted:
“the vapors emitted from butter flavoring are a complex mixture that produces necrosis that cannot be explained by the known toxicological properties of any of its components.” (Hubbs, et al. 2002)
Although popcorn makers began selling still buttery-flavored product labeled “no diacetyl,” Sphere’s Andrew Schneider has been investigating whether a ‘no diacetyl’ claim translates into less health risk to exposed workers and consumers. His sources have consistently said “No.” Now, so does NIOSH Director John Howard.
In a December 23 letter to new OSHA chief David Michaels, the NIOSH Director wrote:
“…starter distillate [which eventually creates diacetyl], acetoin, and 2,3 pentanedione exemplify the lack of evidence demonstrating the workplace safety of potential substitutes for diacetyl; and document some evidence that potential substitutes are also respiratory hazards.”
Not that OSHA’s health scientists really need this official word from NIOSH that compounds of this nature can damage the respiratory system, but it does create an opportunity for OSHA’s new leadership: engaging actively in inter-agency policy discussions to improve the Toxic Substances Control Act. Few could benefit more than workers from a law that improves OSHA’s statutory authority to prevent harm from exposure to chemicals, encourages safer alternatives, and enhances right-to-know.