Why are the vapors released from flavoring chemicals dangerous?
A chemical called diacetyl is used to add a butter-like flavor to food products, including microwave popcorn. Animal studies have shown that rats exposed to vapors from flavoring chemicals have developed severe airway injuries. It is suspected that there is a causal relationship between diacetyl exposure and the development of bronchiolitis obliterans, an uncommon lung disease characterized by fixed airways obstruction. However, this causal relationship has not been firmly established.
