WASHINGTON -(Dow Jones)- Governors of 18 U.S. states on Wednesday urged Congress to stop "harmful" Environmental Protection Agency regulation of greenhouse-gas emissions, saying the agency isn't equipped to deal with "the very real potential for economic harm."

The governors, led by Mississippi Gov. Haley Barbour, made their request in a letter to Senate Majority Leader Harry Reid (D., Nev.), House Speaker Nancy Pelosi (D., Calif.) and their Republican counterparts. The letter was also signed by Minnesota Gov. Tim Pawlenty, a Republican who has been cited as a possible contender in the 2012 presidential election.

"We feel compelled to guard against a regulatory approach that would increase the cost of electricity and gasoline prices, manufactured products, and ultimately harm the competitiveness of the U.S. economy," the governors wrote. "We strongly urge Congress to stop harmful EPA regulation of greenhouse gas emissions that could damage those vital interests."

A spokesman for Reid declined to comment. The EPA and Pelosi's office didn't immediately respond to requests for comment.

The governors' letter ratchets up the pressure on the Obama administration's EPA as it prepares regulate greenhouse-gas emissions from vehicles and stationary sources such as power plants. The rules are due to be finalized by the EPA later this month. EPA Administrator Lisa Jackson has said the regulations for power plants, factories and oil refineries will be effective on a delayed basis, beginning in 2011, allowing companies extra time to plan ahead.

Coal, oil and manufacturing states have warned of the costs of complying, which could involve equipment purchases and other spending. In Congress, multiple measures are pending to hinder the EPA. One measure, from coal-state lawmakers including Sen. Jay Rockefeller (D., W.Va.) would suspend EPA regulations for two years. Another measure, led by oil-state Sen. Lisa Murkowski (R., Alaska) would overturn the EPA regulations.

"A simple delay of EPA action will do nothing to provide relief to Americans looking for jobs or businesses looking to make new investments in our states," the governors wrote in urging Congress to stop the EPA outright and to pass comprehensive energy legislation. "Furthermore, such delay of EPA action only creates more uncertainty in a difficult fiscal environment."

The EPA is acting after a 2007 Supreme Court decision found that carbon dioxide and other greenhouse gases are pollutants under the Clean Air Act and ordered the agency to determine whether to regulate the gas. The Obama administration's EPA last year found that greenhouse gases endanger the public, providing a basis for the rules it has already begun rolling out.

The letter was also signed by West Virginia Gov. Joe Manchin, a Democrat, and Republicans including Alaska Gov. Sean Parnell, and Louisiana Gov. Bobby Jindal. In addition to the 18 state governors, the governors of Guam and Puerto Rico also added their names.

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