Can the General Contractor be liable for injuries related to heat when we have to work on a job with no ventillation and 116F outside. I don't know how much more I can take.

I would say yes. What does OSHA have to say about it? Kinda think that you should be working nights or maybe early AM until it gets real hot then knock off. That's what roofers do around here. Maybe not good for productivity but too bad!

-Hal