In Merck's case, it was building concrete retaining containers for the "purple dirt" (soil contaminated with BENZENE - one of the most carcinogenic substances there is) -- the father of a daycare friend of my daughter was working there as a lead carpenter until he realized what they were working with and what kind of OSHA violations were going on - No MDSDs (or whatever the acronym is for the documentation about the toxic materials that's supposed to be available to workers), no special clothing or precautions of any kind for the people handling the material - because 90% didn't speak English, or knew enough to ask. The guy who knew about it quit the job rather than fight, however.

And this is the facility that Merck wanted to close a few years ago, until they found out how much it would cost them to clean the site up. It was cheaper for them to stay and build new facilities on top of the buried toxic dirt.