First, if 1994 was the LAST time they reviewed the standard, why NOW? (I know the answer, to help the Rat presidential candidate).
Second, maybe (most likely) if the 1994 review under a RAT administration produced no changes in the standard, there shouldn't be a change even now. Sometimes the best action is no action.
Federal law (CAA) requires that the standards be reviewed and if appropriate, changed every five years. The root of this problem is the law, not the agency (though they are a source of plenty of problems on their own). The law (the Clean Air Act) needs to be changed.
The process is completely broken, and changes to the CAA will not save a single life from a CO leak in a furnace or space heater...