quick googling indicates the CAC grew out of HSPD-12 (homeland security presidential directive 12). All federal agencies were supposed to have issued these cards over the last year. Agencies such as USDA already use these for computer access. Everyone else, it's a fancy (and expensive) ID card.

My point is not "OMG mold," it's "OMG, this has been damp too long, and now smells like a wet dishrag, or worse, a wet dog"
That said, nothing would probably happen for the three to four hours mentioned in the other posts, but I wouldn't let it sit more than that, especially on a hot day. Also if it does, consider cleaning your washing machine (with bleach or similar product) and leaving the door open.

1. Your houseplants and pets are used to living at a nice steady 70F. They can probably handle 80-85F, but it would probably be a little hard on them to go much higher.
2. A house shut up with no A/C running on a 90F day is a sure sign that no one's home.
3. To keep CowboyNeal cool.

MOLD? For waiting a couple of hours? You've read too many crazy articles out there "MOLD IS COMING TO KILL US ALL!". :-)

You'd likely think different if you ever had to smell an entire load of clothing that smelled like an old wet dish rag.

I also remember a story about the BBC in its early shortwave days having transmission issues... which they traced to a man living a few miles from the transmitter.
He had lined the underside of his roof with copper, which heated up whenever the BBC was broadcasting.

The BBC fixed it by buying him a space heater.

My FIL works at a coal gasification plant.

One way that this does help with reducing CO2 emissions is that the exhaust of the plant is primarily CO2. Standard coal plant exhaust is still mostly nitrogen, oxygen, CO2, SO2, etc.
What does the plant do with it? Compresses it into liquid, and pipes it up to Sasketchewan. An oil company injects it into old oil fields to recover more oil.
Basin Electric CO2 Sequestration
This is where the CO2 savings come in.

As someone in the field, what about the issues surrounding retrofitting these older plants with new equipment?
IIRC, there are certain changes/repairs/upgrades that can be made, but if they go beyond a certain point of improvement, don't they have to then comply with the Clean Air Act of 1970?
What kind of efficiency improvements could be made to these old plants if they didn't have to comply, or maybe not fully?
It seems like you could decrease pollution overall if you could eke out a few % (eg, burn less coal for same output) without having to overhaul the entire pollution control system.