Originally Posted by Xaccers

The records of what is stored in each tank would have been kept on site, either on an easily meltable computer, or quite combustable paper.
With the physical records there is no need for a person to know what is in each tank, they can just check the records, so when this sort of incident happens, no one is able to give a definite answer as to what is in each tank, and you really need a definite answer when you're sending firemen in to that situation