This is what happened when I used it in my garage when it was raining outside. I used it to remove rust in my rear end housing. When I poured it in it started smoking like crazy so I opened the garage door and turned on my huge fan to blow out the fumes. I finally emptied the acid and washed out the housing. The rear end had the outside just sand blasted. The next morning it was brown and had to have it reblasted. Yesterday I noticed my new headers were rusted. Not to happy.
