How do industrial oil filled transformers catch on fire?

i've been told that internal short circuiting creates sufficient heat

to create acetylene ------i suppose the acetylene exceeds the

pressure rating of the transformer, ruptures the shell,

oxygen then meets acetylene and a very flammable mixture

ignites. Can anyone explain in more detail?How do industrial oil filled transformers catch on fire?then it goes boom. If your looking close enough, you will see the details briefly.