Gas drilling and production involve a lot of steps, and during many of those steps, toxic gases are released into the air.
Some of the gases form ozone, and some of them, like benzene, can cause cancer.
The new EPA rules will require gas drillers to grab those gases before they leak away, or to burn them off, a technique known as flaring.
Gina McCarthy is an assistant administrator at the EPA:
"The steps we're taking today are designed to support responsible production of domestic oil and natural gas, they reduce harmful air pollution, they improve air quality, they protect the public and they do it in a way that more than pays for itself."
Texas has the most active gas wells in the country, with active drilling concentrated in the Eagle Ford shale in south Texas and the Barnett Shale near Forth Worth.
Starting in 2015, gas drillers nationwide will no longer have the flaring option; they'll have to install the capturing equipment.
McCarthy said the extra few years will give the industry time to phase in the required controls:
"There does need to be a period of time for equipment to be manufactured, distributed, training to be done and conducted, and we believe that reasonable period of time will end on Jan. 1, 2015."
Some environmentalists had criticized the phase-in period, but McCarthy says many drillers will go ahead and voluntarily install the equipment early.
That's because the captured gases can be sold, and the costs of the equipment recovered in as little as 60 days.
Congressman Pete Olson of Sugar Land released a statement criticizing the new rules, saying the regulation should have been left to the states.
From the KUHF Health and Science Desk, I'm Carrie Feibel.