Q: FUEL INJECTION CLEANING AND ANTI CORRISION UNDERCARRIAGE TREATMENT

Had this service done at my dealer, after arriving home I parked car in garage. About 30 mins later I had to go into garage to get something and there was a overpowering smell of chemical in closed garage. It gave me a headache it was so strong I could not stay near car inside garage. Was something spilled ? What could cause this? Can this cause damage to other parts of engine? I moved the car outside where it still is. I also had a Hyundai ordered FREE rust corrosion applied under the car due to high salt used in my area. I called dealer and the guy said "oh something just spilled on hot part" park the car outside overnight and it will dissapate. I am afraid this "spill" could have been the mechanic not shutting off some kind of valve before starting. I was told the undercarriage stuff would not cause odor. I DON'T BELIEVE THEM. I have not driven the car yet again since last nite. it is very cold here today, there is no odor in garage now. Your thoughts on this? THANK YOU

My car has 25430 miles.
My car has an automatic transmission.