[Mrmerlin]

booms from the refinery are not good. When you see anything coming out of a smoke stack other than thin white vapors then it usually indicates that some part of the heating unit that it is connected to has failed.

I used to work at Ultramar near San Pedro 1990, and one morning I was taking the samples from the boiler systems and the ground turned orange.
I looked up to a huge orange cloud coming out of the stack , It was a sulfur cracker system, that had failed and was dumping sulfur into the boiler.
Meanwhile I threw the water sample into my car and jumped in and made my way to the outside of the front gate, just as the fire alarms were starting to go off.
In about 10 minutes there were about 30 fire trucks and 10 helicopters and EPA, ATF, Secret service, sheriffs, fire departments, all lined up at the front gate trying to figure out WTF.
So a little white smoke is OK its usually steam, any other colors and you might have to run