For a moment or two last week, it looked like U.S. Sen. David Vitter, R-La., had hit a sweet spot between business interests and environmental movement.

A conservative considered a friend of industry, he joined in the public rollout of a chemical regulation bill he cosponsored with U.S. Sen. Tom Udall, D-N.M., who has enjoyed a reputation as an environmentalist. Udall was a leader in the fight against oil drilling in the Arctic National Wildlife Refuge, and his father, Stewart, who was secretary of the interior in the Kennedy administration, championed the far-reaching Clean Air and Clean Water acts.

Not only that, the measure was saluted by the Environmental Defense Fund, a nonprofit advocacy group that pioneered the successful effort to ban the insecticide DDT from the environment. Founded in 1967, the EDF has pushed to ban whale hunting, phase out lead from gasoline, get McDonald’s to adopt biodegradable packaging and tackle the problems of global warming and climate change.

“Americans shouldn’t have to worry whether chemicals in their homes pose a threat to their families,” EDF President Fred Krupp said in a statement. “With lawmakers coming together from both sides of the aisle, this is the best chance in a generation for us to move past an obsolete and badly broken law to provide strong protections for all Americans. We look forward to working with Senator Udall, the environmental community and other stakeholders to get the strongest bill possible enacted into law. Congress cannot afford to let this historic opportunity slip from its grasp. We owe it to our children and grandchildren to seize the moment and act.”

Louisiana is home to the second-largest chemical industry in the country (Texas is No. 1). Industry groups also support the proposal, which is designed to rewrite the 1976 Toxic Substances Control Act, a law widely regarded as outmoded and ineffective.

“This legislation will offer the kind of predictability, consistency and certainty that manufacturers and the national marketplace need, while also strengthening oversight and providing consumers with more confidence in the safety of chemicals,” the American Chemistry Council said.

That was Tuesday. On Thursday, two other senators — Democrats Barbara Boxer, of California, and Ed Markey, of Massachusetts — released their version of a TSCA update.

“Our citizens deserve nothing less than a bill that protects them — not chemical companies,” Boxer said in a statement.

Boxer has said the Udall-Vitter bill actually will make things worse and result in less protection from toxic chemicals in the environment. An array of environmental organizations have joined in backing her measure in preference to the Udall-Vitter bill. The Natural Resources Defense Council has criticized the Udall-Vitter proposal, and it has tangled with Vitter before: In 2014, he protested what he saw as a too-cozy relationship between the organization and the Environmental Protection Agency in drafting regulations for carbon emissions from power plants and in other matters.

A key point of disagreement over the two TSCA measures involves the degree to which the Udall-Vitter bill would pre-empt state regulations of toxic chemicals in clothing, furniture and elsewhere in the environment. Critics of the legislation say it would rob the states of power to restrict the chemicals in the future and open the way to lengthy delays in federal regulation.

Vitter collaborated in the previous Congress with a Democrat, the late Frank Lautenberg, of New Jersey, on a TSCA rewrite (the new bill is named after Lautenberg). But in that Congress, the Senate was controlled by Democrats, and Boxer was chairwoman of the Environment and Public Works Committee, with jurisdiction over the measure. Despite a lengthy list of bipartisan cosponsors, the bill never made it out of Boxer’s committee.

The 2014 elections gave Republicans a 54-46 majority in the Senate and also expanded their majority in the House. Besides Udall and Vitter, their bill has 15 cosponsors, including Environment and Public Works Committee Chairman James Inhofe, R-Okla., Bill Cassidy, R-La., and seven Democrats. That’s enough Democratic support to provide a filibuster-proof majority in the Senate, if all Republicans line up behind the bill. Boxer and Markey have so far rounded up one cosponsor: Bernie Sanders, I-Vt.

The Environment and Public Works Committee is scheduled to take up the bill Wednesday.

Gregory Roberts is chief of The Advocate Washington bureau. His email address is groberts@theadvocate.com, and he is on Twitter, @GregRobertsDC.