From what I remember reading of it the combination of temperature and
baking time weakened the tanks. They were not pressurized at the time,
the valves were removed. They ruptured during their first refill after
coating, SCUBA tanks are placed in water during filling, so if they go
their not like a bomb. Supposedly makes a hell of a noise and lots of
water thrown all over the place. But the energy is disapated in the
water.