DeGette says her natural gas bill won’t block production

But Exxon, in paperwork on the XTO acquisition filed with the Securities and Exchange Commission, says it will back out of the deal if Congress makes the technique “illegal or commercially impractical.”

DeGette said her bill wouldn’t do that. It brings the practice – often called “fracking” – under the Safe Drinking Water Act and requires disclosure of chemicals used in a way that she said protects proprietary information.

"Good news. My bill would not make hydraulic fracturing illegal, nor would it make it commercially impractical," said DeGette, who said she supports use of fracking in an environmentally sensitive way.

But industry groups are opposing the bill, arguing it would create burdensome requirements that hinder a technique they maintain is safe. Environmentalists fear fracking will pollute underground water supplies.

The hearing is taking place in the Energy and Environment Subcommittee. Exxon CEO Rex Tillerson dodged a question by ranking member Fred Upton (R-Mich.) about whether the proposed legislation would scuttle use of fracking.

Tillerson instead emphasized the importance of fracking to access what are thought to be massive U.S. reserves of shale gas. "Without hydraulic fracturing the gas that's locked in the shale stays locked. It just stays there," Tillerson said.

But without addressing the bill, he said "we see a lot of regulation that comes out of the Congress and the U.S. government that provides little benefit, but there is an enormous propensity to regulate in this country."

XTO Chairman Bob Simpson said he believes Congress is unlikely to halt fracking, saying he sees "no real risk of legislation that would prohibit that practice."

Update: Tillerson, after I filed the post above, said he believed EPA rules would be duplicative of state-level protections and raise the cost of developing shale gas.

This post was updated at 4:52 p.m.