[Pikachu_Dad]

Those tanks are designed to breathe.

So yes, there would be some level of fumes on top of the tank.

My gut tells me that this was a smoke break with a very bad location chosen to do it.

[deport]

So yes, there would be some level of fumes on top of the tank.

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The tank, owned by Key Production Co. Inc., had about 6 inches to a foot of oil in the bottom, Deputy Franklin said. "When there is oil there is always gas mixed in with it," he said, adding that probably gas vapor was venting out of the top of the tank.