But the EPA can step in if it thinks a state isn't being strict enough. That's what happened this week: the EPA took over the air-permitting process for a Corpus Christi refinery. The EPA also warned that it might do that with other Texas plants.
State Representative Carol Alvarado says if that's what needs to happen, then it should.
"What we want is for TCEQ to come into compliance with what the law is asking them to do. There is a gap between the current air permitting process in Texas and what is legally required by the Clean Air Act. We're not wanting TCEQ to do anything that is above and beyond. We want them to be in compliance, just like every other state in this country."
Governor Perry criticized the Obama administration for the EPA's action. But Alvarado says it's not a political move and shouldn't become a partisan fight.
"This is not anything new, this is not something that the current administration has just sprung upon us. Back in 2002, under the Bush administration, they challenged TCEQ about the permitting program and then in 2008 again the Bush administration, they formally disapproved of part of TCEQ's permitting program in 2008."
Houston has long been a focus of clean-air battles. Alvarado represents neighborhoods in the East End, near the largest concentration of petrochemical plants in the country.
"I grew up in the East End. I grew up along the Ship Channel. I grew up breathing bad air for the majority of my life. And I still represent part of the East End. But that air doesn't just stay in the East End, it is all over our city and our state."
Alvarado was joined by the Sierra Club and Democratic state representatives Ellen Cohen, Garnet Coleman, Rodney Ellis and Sylvester Turner. Because of a lawsuit, the EPA has a court-ordered deadline of June 30 to decide whether to strike down the method Texas uses to regulate air emissions.
From the KUHF Health Science and Technology Desk, I'm Carrie Feibel.