I do not recall the story about the EPA and the O-rings, however I DO know the story on the ET foam adhesive.
In the early 1990s, the EPA told NASA they had to switch adhesives used to stick the insulating foam on the External Tank. It seems the old adhesive relied on fluorocarbons, which everyone KNEW were destroying the ozone layer.
The new adhesive was not so good. The foam gets loaded with ice on the launch pad and then peels off hitting the Shuttle tiles when the bird hits supersonic speeds.
It was one such piece of foam that hit the wing leading edge on Columbia and broke a hole in the RCC (Reinforced Carbon-Carbon). That led to losing the second Shuttle.
I was in the meeting at JSC when we briefed them on the weakened RCC on Columbia. I still have my meeting notes in my file cabinet. I am not sure if they replaced it before the accident.
Gotta take a break now and feed the livestock!
It was one such piece of foam that hit the wing leading edge on Columbia and broke a hole in the RCC (Reinforced Carbon-Carbon). That led to losing the second Shuttle.
Are you referring to the heat shield tiles needed for the craft to survive the intense heat of reentry? Columbia exploded on reentry, didn't it?