Republicans in Congress appear to be headed for a showdown with the White House over controversial “secret science” legislation aimed at changing how the Environmental Protection Agency (EPA) uses scientific studies. A deeply divided Senate panel yesterday advanced a bill that would require EPA to craft its policies based only on public data available to outside experts. The House of Representatives has already passed a similar measure. But Democrats and science groups have harshly criticized the approach, and the White House has threatened a veto.

The House and Senate bills are the product of long-standing complaints—mostly from conservative lawmakers—that EPA relies too heavily on raw data that are not easily available to outsiders. Republicans on the House science committee, for instance, have been waging a long-running battle with EPA officials over the release of health data used to support air pollution regulations. The bill’s opponents, however, say the calls for transparency are aimed at blocking the agency from using certain types of confidential data, potentially delaying or imperiling new environmental regulations to industry’s gain.

Both perspectives got airtime during yesterday’s debate in the Senate Committee on Environment and Public Works over S. 544, the Secret Science Reform Act. It would require EPA to base all its rules, assessments, and guidance on data that is “transparent” and “reproducible.” The legislation, sponsored by Senator John Barrasso (R–WY), serves as a companion to a measure that the House approved last month mostly with GOP votes.

Democrats on the panel objected to the Republican majority’s plan to vote on the bill, arguing that the panel had not yet held any hearings on the legislation. (The House did hold hearings on its bill in previous sessions of Congress). “We are considering a legislative conclusion before we have done the legislative investigation,” said Senator Ed Markey (D–MA), one of several Democrats who called for shelving the bill until a hearing could occur.

Panel leaders rejected that idea, and the bill cleared the committee on an 11 to 9 party-line vote. Prior to that vote, Republicans beat back a couple of Democratic-sponsored amendments: one that would have restored EPA’s ability to rely on any peer-reviewed science, and another that would have required EPA to disclose only the funding sources, not the raw data, of studies the agency wants to use. Barrasso said the amendments would “defeat the purpose of the bill.”

On a voice vote, the committee did adopt an amendment that would prohibit any effort to bar EPA and other federal scientists from using common scientific terms. In offering the amendment, Senator Barbara Boxer (D–CA), the committee’s top Democrat, said she was alarmed by efforts by Republican officials in Florida and Wisconsin to allegedly bar certain state employees from talking about climate change.

Democrats say they plan to use the bill to call out Republicans for their party’s rejection of climate science. And Boxer lashed out at Republicans for supporting the measure just after the panel had advanced another bill that would give EPA more power to request data on chemicals’ risks and to regulate toxic substances. “This is insane, it’s just a joke,” Boxer said.

The secret science bills represent just one front in Republicans’ efforts to attack President Barack Obama’s environmental agenda, which they view as too costly to businesses and the economy. House Republicans have also pushed a bill to overhaul how EPA obtains scientific advice from its panel of independent scholars, and another measure to boost public participation and agencies’ data disclosure and analysis requirements. All three bills, approved by the House on mostly party-line votes, have received veto threats from the White House.

White House officials—along with Democrats, a bevy of scientific organizations, and public-interest groups—argue that the secret science legislation would force EPA to ignore numerous studies. They say that not only do many studies contain public health or industry-submitted data that are confidential, but the legislation provides too little funding for EPA to obtain all the necessary raw data. And many studies, such as longitudinal surveys, are not realistically “reproducible,” scientific organizations worry.

S. 544 now moves to the full Senate, which could act on it at any time. The House and Senate would then have to reconcile any differences in their bills and approve one measure to send to the White House—where it’s sure to meet a cold reception.