I think that's just No OSHA Compliance - it's not as if it were designed for human workers, after all.
To my mind, Nightmarish Factory is a factory that's shown to be a Fate Worse than Death to work in, while No OSHA Compliance is simply a very dangerous factory. They have different uses, too - No OSHA Compliance usually involves a set-piece for a fight or chase scene, with how dangerous it must be for the workers typically only acknowledged through Fridge Logic. With Nightmarish Factory, the emphasis is on the horrible working conditions and often how the workers suffer from them. The emphasis is more "hellish environment" then "dangerous location".
As a rule of thumb, if you don't see anyone actually working there, it's not likely to be a Nightmarish Factory.
edited 14th May '11 11:39:17 AM by nrjxll
Added an example. I've Seen It A Million Times; I think this page just needs more pimping.

Nightmarish Factory looks like a good trope, but only has four examples. Can anyone think of any more? (Off the top of my head, Oddworld is a good example.)
That's Feo . . . He's a disgusting, mysoginistic, paedophilic asshat who moonlights as a shitty writer—Something Awful