Continuing this sad tale, we saw the loss of a launch because of faulty O-ring design caused by small, but significant, warpage from the weight of the vehicle resting on its side during the O-ring installation.
That's not what caused the O-ring failure, and the vehicle was attached vertically in the VAB, well after the SRBs were fully assembled and mated to the tank. The temperature at launch was below freezing, and about 25 degrees lower than any previous launch. The O-rings lost most of their flexibility due to the cold and failed to seal the joint as a result.
And then, there was the loss during re-entry from another vehicle because of icing issues - even though NASA had a waiver to continue using freon for de-icing which would have eliminated this problem, but changed to a different, less effective, but MORE Politically Correct compound. Granted, the actual icing issue didn't cause the loss, but the ice build-up and the impact of the ice-chunk DID result in another senseless, tragic loss.
The Columbia accident wasn't caused by ice either - it was a block of insulating foam that broke off from the tank and struck the orbiter. Very little ice ever formed on the external tank due to the insulation.