They look good, I also like the 2nd one best. The lighting is best in that one and the clear safety glasses work better than the shaded ones in #3.
Although, I must say that I'm having a hard time separating the photos from my instinct to yell at you "Get back to work!".
Most people (or work sites/companies) wouldn't be all that happy about someone photographing workers in an environment like that. For one thing, it could distract the workers, which is a safety issue...but I think they would also be uncomfortable about the possibility of compromising photos. If you snapped a photo just when someone lifted their safety glasses or took of their hardhat...it could make someone look bad.
A week or so ago, I was up at an oil drilling rig that was being overseen by Shell. After taking my measurements I grabbed my camera to snap some shots to go along with the measurements. The safety inspector told me that I was supposed to fill out a form about using that specific piece of equipment. Good grief...I've never run into that before. He was pretty impressed with my camera though