The ingredient is diacetyl. I don't know what the exposure to it is that is necessary to show this link, but they talk about industrial exposure.
It also says that diacetyl is an ingredient in beer and wine. Just wanted to correct this: Diacetyl is a by-product of certain types of yeast fermenting. If the beer or wine is given a solid diacetyl rest, the yeast will often clean up most of that. It's especially prominent in ales (top-fermented beer). If you taste a buttery, oily taste at the backend of a beer, it's probably diacetyl.
It also says that diacetyl is an ingredient in beer and wine. Just wanted to correct this: Diacetyl is a by-product of certain types of yeast fermenting. If the beer or wine is given a solid diacetyl rest, the yeast will often clean up most of that. It's especially prominent in ales (top-fermented beer). If you taste a buttery, oily taste at the backend of a beer, it's probably diacetyl.