A proposal for a safe exposure level for diacetyl.

Diacetyl is a naturally occurring compound that has been used in concentrated form as a food additive, particularly in butter flavorings. Inhalation of diacetyl and butter flavoring fumes has caused a variety of respiratory diseases in workers and consumers including bronchiolitis obliterans (BO), a relatively rare, severe, and irreversible lung disease. A safe level of exposure to diacetyl has not been established. We review the literature on diacetyl and flavoring toxicity and critique a recent proposal for an occupational exposure limit (OEL) of 0.2 ppm for diacetyl. We present unpublished data and novel analyses in support of our proposal for a safe level of exposure. Our findings indicate that a safe level of exposure exists around or below a time-weighted average of 1 ppb for an eight-hour workday. The levels of exposure we found to be unsafe include ranges that popcorn consumers may potentially be exposed to, indicating a risk of severe lung disease (including BO) for some consumers.

A case of occupational peritoneal mesothelioma from exposure to tremolite-free chrysotile in Quebec, Canada: A black swan case.

BACKGROUND: Tremolite contamination has been proposed as the cause of mesothelioma in workers exposed to commercial chrysotile. The asbestos industry and scientists it has sponsored, for example, have argued that commercial chrysotile does not cause peritoneal mesothelioma. METHOD: Case report of peritoneal mesothelioma in a mill worker from a tremolite free Canadian mine. RESULTS: Reports from pathology and occupational health and safety panels conclude that this mill worker developed work-related peritoneal mesothelioma. CONCLUSION: Chrysotile without tremolite can cause peritoneal mesothelioma.