A pair of senators is urging the White House Office of Management and Budget not to let the Environmental Protection Agency sully the reputation of hydraulic fracturing, or “fracking,” the controversial natural-gas drilling method.

Sens. Mary Landrieu (D-La.) and Rob Portman (R-Ohio) are asking OMB’s regulatory chief to ensure that EPA “reaches sound and well-supported scientific conclusions” when finalizing an explosive draft report that linked fracking to groundwater contamination in a Wyoming region.

“A false-positive link between hydraulic fracturing and groundwater contamination could form the basis for costly new regulation,” they write in a letter sent Monday to Cass Sunstein, who heads OMB’s Office of Information and Regulatory Affairs.

“Unwarranted regulation of hydraulic fracturing could have substantial economic impact on the natural gas industry, the consumers and businesses that rely on it, and the millions of jobs that it directly or indirectly supports,” the senators add.

Landrieu is a prominent Capitol Hill ally of oil-and-gas producers, and Portman headed OMB under former President George W. Bush.

The letter adds a new wrinkle to the furor over EPA’s December draft report that linked the increasingly widespread gas drilling method to contamination in the Pavillion, Wyo., region.

The preliminary conclusions, if borne out, would dent the petroleum industry's contention that there’s no evidence to support claims that fracking chemicals are fouling groundwater.

The study has come under attack from energy industry groups and industry allies who call EPA’s methods sloppy and inaccurate.

EPA has defended the rigor of the draft study, which it is subjecting to peer review.

But the agency is also warning against using the results to draw broader conclusions about fracking and groundwater pollution, noting that the fracking under review in Wyoming occurred under atypical conditions.

The Pavillion study has arrived as federal agencies are mulling various plans to toughen oversight of fracking even as the administration vows to support continued expansion of natural-gas production.

Fracking involves high-pressure injections of water, chemicals and sand to open up fissures in rock formations that enable trapped oil and natural gas to flow. The method is helping to enable a U.S. natural-gas production boom but bringing concerns about water pollution and other public health threats along with it.

Landrieu and Portman are specifically urging Sunstein to ensure the report is considered a “highly influential scientific assessment” under the Information Quality Act (IQA).

The tag would ensure the report gets the review it deserves, the lawmakers say.

“We respectfully urge you to ensure that EPA follows OMB guidelines for appropriate vetting of this important study,” states the letter to Sunstein, the former Harvard law professor that environmentalists view with a skeptical eye.

The IQA is a very brief statute that was buried in a 2000 appropriations bill that has given outside parties — usually industry groups — an additional avenue to challenge data from EPA and other agencies.

It says federal agencies must ensure the integrity of data they disseminate and allow outside parties to submit petitions for corrections.