I seem to be sweating antifreeze?

We had to do some work that took several hours in a hot boiler room today. We all sweated like pigs despite stripping to our waists. At one point my co-worker Merl said to me "Carl, what's that green stuff on your head?" I wiped it from my forehead and it was indeed green sweat. It was on my back and chest as well. I smelled it and it smelled like ethylene glycol - common antifreeze. Something I know well from having had cars with overheating problems. Once we finished and moved to cooler environs I stopped sweating but I am perplexed by the occurrence. Otherwise I feel fine and have never had anything happen like this before.