It sure looks like someone tapped off that 240 plug with some #12- maybe for 120? Would be kind of silly with that receptacle right next to it!
With the use of the LB, pipe, etc, I think we can assume this was done by someone in the maintenance department- and not some restless production guy.
That "somebody" really needs to be fired- NOW. Reasons:
1.) Too many amps on that #12;
2.) Bootleg neutral / parallel paths; and,
3.) General disregard, or knowledge, of the proper way to do this.
I was sent to install GFI breakers for all the welding receptacle at this company, anything thats cord connected they want GFI protection. The GFI breaker that feeds that box kept tripping, you see what I found when I opened the box.
John's right about everything he posted except it was an electrician who tapped out of that box for a 120v MH light.
The sign is a "Danger Confined Space" sign in a group of silos.