It's a blue collar occupational hazard.
I knew a guy who worked at a smelter. I can't remember why but there were chunks of cyanide on the floor the size of hockey pucks. And molten metal. Everywhere molten metal. The workers tended to regulate their moods with coke and weed. Except my buddy, who failed a drug test, did some treatment, and realized that smelters sober are safer than smelters high but substantially more terrifying.