I have a boiler furnace filled with antifreeze. It was serviced today, now my eyes and throat burn. why?

The man cleaned my furnace with a brush inside and said the h20 psi was boarding a little high and he opened the pressure relief valve for a second. that was 11 hours ago and it still burns. it is in a building on my property and I have the door open hoping the burning will stop, maybe it just spilled on something hot? Is this dangerous? Why did this happen? Is it the propane, or antifreeze fumes, what do I do?