I beg to differ!! I had one rupture( there is a difference) about 6 1/2 yrs ago when I was kneeling beside it monitoring the pressure and checking the pressure relief valve. Cracked the left tibia and femur and shattered the bones in the left hand, so just because you haven't heard of it doesn't mean it didn't happen.
Mike, if you could have inspected the inside of the tank that ruptured would you have been able detect where the failure might occur and was there a significant amount of rust present? Also, was the tank a commercially manufactured air tank or a converted freon tank? Just curious. Thanks