WASHINGTON – Dozens of congressmen are looking into claims from a conservative think tank that the Environmental Protection Agency is exhibiting favoritism toward liberal groups in addressing Freedom of Information Act requests.

The Competitive Enterprise Institute, in a report issued last month, maintains that the EPA is making it more difficult for groups that favor a smaller federal government to access public records.

Specifically, CEI asserts that the EPA is waiving FOIA fees for what it describes as left-wing groups – like the Sierra Club, the Natural Resources Defense Council, and EarthJustice – while it “systematically denies waivers for groups on the right,” according to CEI Senior Fellow Christopher Horner.

Horner said his research shows that from January 2012 to Spring 2013 the fees for “green” groups were waived in 75 out of 82 cases. Meanwhile, the EPA effectively or expressly denied his request for fee waivers in 14 of 15 FOIA instances over this same time period. Horner’s appeals of the EPA decisions to deny his fee waivers were rejected.

Further review, Horner said, established that “green” groups proved successful in getting their fees waived 92 percent of the time. Meanwhile, Horner’s requests for fee waivers on behalf of CEI and the American Tradition Institute were rejected more than 93 percent of the time. EPA documents further showed that other conservative groups encountered problems. Judicial Watch and the National Center for Public Policy Research each went two-for-four in waiver requests. The Franklin Center had both its requests denied and the Institute for Energy Research was rejected in its lone request.

Rep. Tim Murphy (R-Pa.), an EPA critic, said the FOIA fees “can exceed six figures for nonprofit organizations.”

“This demonstrates a clear pattern of favoritism for allied groups and a concerted campaign to make life more difficult for those deemed unfriendly,” Horner said. “The left hand of big government reaches out to its far-left hand at every turn. Argue against more of the same, however, and prepare to be treated as if you have fewer rights.”

The CEI claims have captured the attention of conservative lawmakers, some of whom have been fighting the EPA for years. Rep. Ed Whitfield (R-Ky.), chairman of the House Subcommittee on Energy and Power, who is still wrestling with the agency over regulations that affect the nation’s coal industry, blasted the EPA over “political favoritism occurring within its agency.”

Whitfield said the Obama administration is engaged in “a pattern of conduct in which this administration rewards its friends and punishes its opponents.”

“We are now finding out that EPA routinely grants fee waivers to its favored left-wing groups who demand a more intrusive and powerful EPA, but systematically deny waivers for free information from any group that EPA disagrees with,” Whitfield said. “America will not stand for a government that rewards its friends and punishes its opponents in this discriminatory fashion.”

During an appearance before the House Energy and Commerce Committee last month, Acting EPA Administrator Bob Perciasepe insisted that the agency’s policy is “to treat everybody the same.” Subsequently, the EPA asked its Office of Inspector General to review the matter. The OIG is still reviewing the request.

But the GOP-controlled House appears to be in no mood to wait. A letter to Perciasepe dated June 5 informed him that the signatories, 35 Republican lawmakers, are “extremely concerned about the apparent bias shown in the FOI process at EPA.”

“This activity calls into question the objectivity of the FOI employees at EPA and undermines public confidence in an agency that is charged with protecting our air and water,” the letter said.

The lawmakers, led by Rep. Steve Scalise (R-La.), chairman of the Republican Study Committee, a conservative GOP caucus in the House, noted that information about the alleged favoritism displayed by EPA became public about the same time as the Internal Revenue Service and the Department of Justice were being investigated for “abuses of power.”

The House Oversight and Government Reform Committee is investigating claims that the IRS targeted Tea Party groups seeking tax-exempt status. The panel also is trying to determine if Attorney General Eric Holder lied during testimony before the committee regarding his involvement in the Associated Press e-mail scandal.

“In the case of the IRS, as with the EPA, it appears as though conservative groups were targeted as well,” the letter said.

The lawmakers asked Perciasepe to inform them of who in the EPA is responsible for granting waivers and what sort of procedures are in place to assure that bias doesn’t occur in waiver requests.

Rep. Lamar Smith (R-Texas), chairman of the House Science, Space, and Technology Committee, and Rep. Paul Broun (R-Ga.), chairman of the House Oversight Subcommittee, sent their own letter to EPA Inspector General Arthur A. Elkins Jr. requesting information about how his office intends to conduct its investigation.

“EPA’s actions are cause for concern in light of similar allegations at the Internal Revenue Service (IRS) that the agency is targeting conservative political groups for unfair and improper screening,” the lawmakers wrote. “These discriminatory actions reflect an unfair and unequal application of the law, designed to clearly dissuade people and groups of a different political mindset than the administration. Such actions can have a chilling effect on the public, and raise questions about the integrity of critical agencies.”

As part of the review, Smith and Broun asked Elkins to determine “whether these are the actions of a few individuals, or the philosophy of leadership at EPA.”

Murphy said EPA critics, like the U.S. Chamber of Commerce, maintain the agency provides some green groups with “preferred customer status” to coordinate friendly lawsuits against the federal government in a procedure known as “sue and settle.”

An environmental group can use documents obtained under the Freedom of Information Act to file lawsuits contending the EPA should apply tougher environmental regulations. Rather than engage in litigation, the EPA settles the lawsuit and accepts the environmentalists’ demands to impose stronger regulations.

The result, Murphy said, is billions of dollars in new regulations passed along to consumers in the form of higher electric bills.