From the AP:

The EPA is trying to put to rest what it calls a "myth" that it is going to crack down on farm dust.

In letters to two senators last week, Administrator Lisa Jackson said the agency won't expand its current air quality standards to include dust created by agriculture.

Republicans and some farm-state Democrats have used the issue on the campaign trail, arguing that the EPA is set to penalize farmers for everyday activities. Republican presidential candidate Herman Cain said in a recent debate that the agency is "out of control" and was preparing to regulate dust.

Republicans in Congress have used the hypothetical dust rule as an argument against government regulations they say could eliminate jobs. Nebraska Sen. Mike Johanns and South Dakota Rep. Kristi Noem, both Republicans, have pushed legislation that would block the rule if it had been proposed.

For more, see: EPA tries to put to rest 'myth' of farm dust rules