Safety Knights

If you truly want to comply, then that would just be a scheduling part on your end. You'd just have to plan on the new temp workers to essentially only be "partially productive" for several days. The only way around that would be to prove that they've been basically working in the same (or hotter) work environment for the past week or two.

As Drew kinda said you would have to get some kind of proof. That proof would possibly need to come from the labor agency. It's a sticky one. OSHA stance on temp worker safety is that the controlling entity (the prime GC) is the one whose the MOST responsible. They don't really look at the agency unless it's a fatality in my experience. You could see if they'd bite on a release form that absolves you of responsibility given the situation. OSHA would likely balk at that across the table, but it may work in court. You could approach the agency and assist them in training their workers BEFORE they come to the site. You could find an agency that does that training already.

The ultimate solution is usually a combination of steps based on available resources and partnerships with the stakeholders. 100% compliance with temporary workers is unlikely now or when it becomes law. This is why the new rules will most likely be a disaster one way or another because a lot of it is social activism. Yes, we need to protect workers but we need to be realistic. So, do what you can with what resources you have, get the stakeholders involved, share resources and document the hell out of it. That's the best you can probably hope for at this point. Train them at the site orientation if you work for a large GC. A captive audience is captive, so add it to the agenda. Make sure the basic availability of water, shade, breaks, PPE, etc. is in place where feasible. Doing what you can do with what you have and whom you have to deal with is better than nothing when 911 is called.

As described, the bottleneck is at the labor agency. Address it there. Get the training running there before they come to you. If it mattered that much to me, I'd walk into the labor agency's operations manager and ask him if he likes avoiding OSHA fines and take it from there. He who dares, wins.