WASHINGTON – A federal investigation into companies’ use of diesel fuel in fracking fluids – a concern because of its potential to contaminate drinking water sources – has prompted state regulators to have their own look into the practice.

The U.S. House Energy and Commerce Committee recently reported that gas and oil companies used 32.2 million gallons of diesel in fracking fluids in several states between 2005 and 2009, including 1.3 million gallons in Colorado.

Hydraulic fracturing is a process of recovering natural gas by pumping water, sand and chemicals into underground wells at high pressure.

The process has been used extensively to extract methane from coal beds in the San Juan Basin.

Diesel contains toxic elements that are believed to be carcinogenic or can cause damage to the central nervous system, liver and kidneys. The Colorado Oil and Gas Conservation Commission investigation will try to find out if any drinking water sources were contaminated.

The commission will be reviewing its database and the reports submitted by well operators, and cross-checking them with samples from water wells, said commission director David Neslin.

However, he said that even if diesel was used in hydraulic fracturing in Colorado, a number of regulatory requirements are in place to ensure that fracking fluids do not come into contact with groundwater.

Those regulations include requiring wells to be cased with steel pipes and the casing to be surrounded by cement to create a hydraulic seal. It also means that well pressure is monitored during hydraulic fracturing.

“Even if it turns out that diesel fuel was used for this purpose in Colorado, we believe that our rules would have ensured that groundwater was protected,” Neslin said. “Whenever issues of this sort are raised, we look into them because the protection of groundwater is an important part of our mission,” he said.

The House committee investigation released Monday found that none of the gas and oil companies tracked whether they conducted hydraulic fracturing near underground drinking water sources.

However, the three largest companies, Halliburton, BJ Services and Schlumberger, told the committee they stopped using diesel fuel when breaking up coal-bed formations, which often are closer to water sources. Three smaller companies said they did use a limited amount of diesel-containing fluids in coal-bed methane wells, but they did not say how close those wells were to drinking water sources.

The EPA requires that companies using diesel fuel in fracking receive a permit under the Safe Drinking Water Act, but the investigation found that no state or federal regulators issued such permits.

U.S. Rep. Diana DeGette, D-Denver, said the findings lend urgency to passing the Fracturing Responsibility and Awareness of Chemicals Act. The proposed legislation would require gas and oil companies to disclose the chemicals used in fracking fluids, closing the so-called “Halliburton loophole” that exempts hydraulic fracturing from EPA regulation except when diesel fluid is used.

Rep. Jared Polis, D-Boulder, plans to reintroduce the act later this year along with DeGette and Rep. Maurice Hinchey, D-N.Y., said Lara Cottingham, Polis’ press secretary.

“Since natural gas is a bridge fuel and something that President Obama has indicated he wants to develop further, we are hopeful that Republicans will be willing to reach a compromise to ensure that future natural gas development does not endanger the safety of our communities,” she said in an e-mail.

However, she added, “with Republicans in control of the House, moving any Democratic-sponsored legislation forward will be more difficult.”

U.S. Rep. Scott Tipton, R-Cortez, maintains that states are doing a good job regulating hydraulic fracturing and that Congress doesn’t need to get involved, said Josh Green, Tipton’s spokesman.

Karen Frantz is an American University intern for The Durango Herald. Reach her at herald@durangoherald.com.