Alan,
Both are excellent in my view.
All your factory shots show the gritiness of what's going on in Chinese factories. Basic, hard stuff.
Although I would have been very happy seeing only the black and white version, the first shot has just enough color to emphasize the darkness of everything else, making it my first choice.
Charlie
I'm not normally a fan of colorized treatments Alan, but your first version is an excellent application of the technique and well suited for the effect.