On one of the threads here on FR concerning the "foam", IIRC , there were some Freepers who stated that the reason the "foam" composite was changed on the tanks, was due to the complaints from the "Save-The-(fill in your favorite sea creature here)."
They complained that after the tanks completed their tasks, and fell back into the ocean to be retrieved later, the "creatures of the sea", who mistook it for a food scorce, were dying because of it's "toxic" properties.
So NASA tried to come up with a substitute, and what they are using now was the substitute.
IIRC,( and if any Freepers can check this to see if I got it wrong),the tank that was used on the ill-fated was the FIRST application of the material. THAT tank was to be used on a previous shuttle flight, but that flight was canceled, the tank was "unused", so it was "returned to inventory."
The tank(the one with the FIRST attempt at applying the "new" insulation,) was brought out of "storage" because the other tanks were already with other shuttles getting prepared for future launches, so it was put into use on the mission that ended in such tragedy.
It's not like I have ever been wrong about something before,(at least according to my wife,)but IMHO, what I posted here was (seared....seared I tell you) close to what I remember freepers explaining about the "foam".
Oh!, I agree totally.