Texas to challenge US greenhouse gas rules

* Texas suit one of several to challenge EPA

* EPA pursuing CO2 rules if Congress does not act

DALLAS Feb 16 (Reuters) - Texas on Tuesday said it will challenge the federal government's authority to regulate U.S. greenhouse gas emissions in court, the latest in what could be a slew of such lawsuits.

Texas, which leads U.S. states in carbon dioxide emissions due to its heavy concentration of oil refining and other industries, will see a major impact if U.S. mandatory emissions reductions become a reality.

In December, the Environmental Protection Agency ruled that greenhouse gases like carbon dioxide endanger human health, opening the door for the agency to issue mandatory regulations to reduce them.

Texas said it had filed a petition for review challenging the EPA's "endangerment finding" with the U.S. Court of Appeals for the D.C. Circuit. Texas has also asked the EPA to reconsider its ruling.

"The EPA's misguided plan paints a big target on the backs of Texas agriculture and energy producers and the hundreds of thousands of Texans they employ," Texas Gov. Rick Perry said.

The U.S. Chamber of Commerce and U.S. iron and steel makers have also signaled they will file lawsuits.

Instead of fighting government regulations, environmental groups said, Texas should focus on building cleaner energy sources.

"Gov. Perry should win an Olympic medal for taking the environment downhill," said Luke Metzger at Environment Texas, referring to the ongoing Winter Olympics in Vancouver. "Global warming is the greatest environmental threat facing Texas and the planet and Gov. Perry's obstructionism puts the state at great risk."

Conservative Republicans like Perry have been evoking the specter of job losses in the debate over regulating greenhouse gas emissions -- a hot-button issue at a time of high joblessness and economic uncertainty.

The EPA is threatening to regulate carbon emissions if Congress will not. In June, the House of Representatives narrowly passed a cap and trade bill that would allow industry to buy and trade pollution permits, but it has stalled in the Senate.

President Barack Obama would rather have Congress act on a bill that could provide more protections for industry while also accomplishing more comprehensive pollution control. But he is using the threat of EPA regulation to encourage lawmakers.

Some prominent Senate Democrats have predicted that comprehensive climate control legislation, including a cap and trade mechanism, will not pass this year.