What would cause an egg to explode?

[dieselgrl48]

Usualy hairline cracks before incubating or just Old egg's.I had a turkey egg go POOF a friend had brought some for me to incubate.PHEW! It makes a smelly mess for sure.

 

[kathyinmo]

Exploders.
Some causes listed are:
Dirty eggs from nest.
Dirty nests.
Floor eggs.
Eggs improperly washed; eggs wiped or cleaned with contaminated cloth or buffer.
Dust from breeder house, cooler, transport, etc.
Water condensation on eggs (sweating).
Water sprayed, fogged, or splashed on eggs; eggs dipped in contaminated solutions.
Contamination from earlier exploders, leakers, or broken eggs.
Contamination from handling eggs with dirty hands or equipment.
Contaminated setter flats, air filters, water (humidity) system.

I found that, here .... http://edis.ifas.ufl.edu/aa204

Oopppps, that's not the correct place. Shoot, now I can't find it!
Anyway, that is copied and pasted from where ever I found it!