Nationally syndicated radio host Rush Limbaugh repeated a debunked theory that Environmental Protection Agency (EPA) regulations banning Freon and other chlorofluorocarbons (CFCs) caused the February 1, 2003, destruction of the space shuttle Columbia. An independent review board investigated the Columbia disaster and found that that the accident occurred because a piece of insulating foam broke off from the shuttle's external tank during flight, severely damaging the shuttle's ability to survive the heat of re-entry. The “theory” Limbaugh promoted is that the EPA regulations forced NASA to stop using Freon in the insulating foam, which weakened its ability to stay attached to the shuttle's external fuel tank. In fact, Freon was used to build the section of insulation foam that broke off from Columbia's external fuel tank; according to the review board's report, NASA stopped using Freon to make that section sometime in 2002, after Columbia's tank had already been built.

The United States and other countries have phased out Freon and similar CFCs because they break down the Earth's protective ozone layer over a prolonged period of time.

Limbaugh brought up this theory, which he said was “going around,” after a caller complained about the EPA's regulation of ammonia. Limbaugh then attacked environmental regulations, and said that he was “inclined to believe” a rumor that the “banning of Freon actually caused ... the Columbia shuttle accident,” claiming: “They had to use something else to cause the foam to bond to the fuel tank, and it was not nearly as good as Freon was.”

But the Columbia Accident Investigation Board (CAIB), which reviewed the accident and issued a report detailing its physical and organizational causes, found that, on Columbia, the particular section that broke off had been built using Freon, before NASA stopped using it to make that part of the external tank's insulation. As part of its report, the CAIB reviewed (very large PDF, 34 MB) the “history of foam changes and debris events” (section 11.3), noting that environmental regulations had caused changes to the composition of the different types of foam used to insulate the shuttle's external tank. The piece of foam that fell off during launch -- part of the left bipod ramp of Columbia's external tank -- used CFC-11, a type of Freon also known as Freon-11. In 2002, after Columbia's tank had already been built, the report indicated that NASA stopped using CFC-11 in the bipod ramp foam.

From the August 3 edition of The Rush Limbaugh Show:

[CALLER]: The EPA -- they wanna get rid of the ammonia emissions. They want the guy to spread it up in the air so it lands on the field, and then come and knife it in. So then they would get rid of the ammonia emissions and the nitrogen. I don't know what it was, but it was the most asinine thing I've ever heard of. And the EPA's gonna be awful if they do that.

LIMBAUGH: I'm not surprised. You know something about the EPA -- there is a theory going around that EPA rules actually may have caused the shuttle Columbia disaster. It goes like this. They used to use Freon in the ingredients of the foam that they spray on the -- that solid fuel tank. It's that foam that fell off -- that chunks of it fall off, and the second to go shuttle mission created a hole in the wing and led to the disaster on re-entry. They can't use Freon anymore. They had to use something else to cause the foam to bond to the fuel tank, and it was not nearly as good as Freon was. And that's why the chunks started coming loose. And so they came up with some other substance that is a little stickier and causes the stuff to bond better, but it still doesn't work as well as Freon did.

So maybe -- a lot of people are beginning to think that the banning of Freon actually caused the shuttle accident, the Columbia shuttle accident, two flights ago. And I'm inclined to believe it when I hear this. Limits on manure on a farm, for crying out loud. We've gotten along just fine with all the manure that happens naturally on a farm.

This is what happens, folks. Bloated government, big bureaucracy, a bunch of people -- oops -- that was the Club G'itmo Soap-On-A-Rope falling from its perch above the golden EIB microphone.