While we're on the subject of explosive vapors, let's not forget our old friend gasoline. One day when I was running the auto shop at a state vocational trade school in Tennessee, I walked to the main office just after class was dismissed for the day to run some off a test I was preparing to give on the copier. About 30 minutes later, I stepped back into my shop, and was greeted by the overpowering smell of gasoline. One of the repair bays with a 2-post hydraulic lift had a Pontiac on it in the middle of a transmission change, and the students had left the lift raised at the end of the day. When they shut off the air compressor which was part of the daily routine, the lift began to lower itself slowly. The rear hydraulic cylinder had gotten ahead of the front for some reason, which jammed the front lift and stopped its travel. The car was at about a 45 degree angle, and about 5 gallons of gas had spilled out of the filler neck behind the license plate. The fumes filled the whole shop.
Now, here's the "rest of the story"- - - - -This happened in early November, and the temperature hadn't quite gotten chilly enough for the two huge natural gas furnaces at ceiling level to start working. Td one of them had lit off with the shop full of fumes, the entire back of the school building would have ended up a couple of blocks away! I opened all the bay doors very carefully, and let the place air out thoroughly before turning the compressor back on to lift the car back to a level position. I also borrowed a camera and took several pictures to illustrate my 2-hour safety lecture to the entire class the next day!
Jerry
