Sen. Barbara Boxer (D-Calif.) has helped to lead efforts to overhaul the nation’s chemical safety laws. (Win Mcnamee/Getty Images)

Congress has reached agreement on the most sweeping overhaul of U.S. chemical safety laws in 40 years, a rare bipartisan accord that has won the backing of both industry officials and some of the Hill’s most liberal lawmakers.

The compromise, which lawmakers unveiled Thursday, will provide the industry with greater certainty while empowering the Environmental Protection Agency to obtain more information about a chemical before approving its use. And because the laws involved regulate thousands of chemicals in products as diverse as detergents, paint thinners and permanent-press clothing, the result also will have a profound effect on Americans’ everyday lives.

The Toxic Substances Control Act, which has not been reauthorized since President Gerald Ford signed it into law in 1976, has come under sharp criticism from all quarters, including from environmentalists who back stronger federal oversight and from chemical companies that are now subject to a patchwork of more-stringent rules in some states.

The measure has the tacit approval of the Obama administration and the top Democrat on the Senate Environment and Public Works Committee, Barbara Boxer (D-Calif.). It also has the backing of a broad coalition of industry, trial lawyers, public health advocates and many, though not all, environmental groups.

The measure could come up for a vote in both chambers as soon as next week. After passage, the EPA must start reviewing at least 10 toxic chemicals that permeate communities across the country, a list that is likely to include asbestos, formaldehyde and flame retardants. Many are interwoven into people’s experience with everyday products, including the ink on their morning newspaper and the fabric protector on their family’s sofa.

“People believe when they go to the grocery store and go to the hardware store and they get a product, that product’s been tested and that product’s safe,” Sen. Tom Udall (D-N.M.), one of the key authors of the legislation, said at a news conference in front of the Capitol. “Well, that isn’t the case.”

Sen. Edward J. Markey (D-Mass.), who worked on landmark measures revamping the Clean Air Act and the Superfund program and helped forge this week’s compromise on chemicals, said “it could be one of the most historic moments in environmental law in our country.”

The improbable deal, which both sides have pursued since President Obama first term in office, gives the EPA the power to require companies to provide health and safety data for untested chemicals and to prevent substances from reaching the market if they have not been determined to be safe. Under current law, the agency must prove that a chemical poses a potential risk before it can demand data or require testing, and that substance can automatically enter the marketplace after 90 days.

In the past four decades, the EPA has required testing for just 200 of thousands of chemicals, and it has issued regulations to control only five of them. More than 8,000 chemicals are produced in the United States at an annual rate of more than 25,000 pounds each, according to the agency.

Under the bill, instead of going through a lengthy rulemaking process to trigger product testing, the EPA can order companies to test their new products. The measure also imposes user fees on industry to help expand the testing of chemicals.

In return, chemical manufacturers will be subject to a single regulatory system, although states will still have the right to seek a federal waiver to impose their rules on a given chemical. Currently, California, Maine, Maryland, Minnesota, New York, Oregon, Vermont and Washington have placed their own restrictions on some chemicals in the face of federal regulatory inaction.

American Chemistry Council President Cal Dooley, whose group represents dozens of chemical companies as well as major U.S. automakers and manufacturers of consumer goods, said his members were willing to disclose more information about their products in exchange for a more uniform standard.

“Not having one federal regulation guiding products onto the national marketplace is really problematic,” Dooley said. The bill “does strike what we see as an appropriate balance.”

Sen. David Vitter (R-La.), who co-wrote the bill with Udall, said conservatives were motivated out of concern for public health and “the need to ensure that Americans remain on the cutting edge of science and innovation. That was threatened.”

Republicans did win some key concessions, including some protections for confidential business information and requirements that the EPA base its risk determinations on up-to-date science.

The bill’s provisions include prioritizing the review of chemicals stored near drinking water as well as those that are human carcinogens and highly toxic with chronic exposure. House Democrats were still seeking to insert language that would allow some states in the midst of regulating chemicals the chance to finalize those actions before the EPA starts reviewing its first batch of chemicals under the law.

Many trial lawyers have been lobbying these Democrats to back it, because it updates the landmark law without depriving them of the right to sue.

Environmentalists, by contrast, remain split. Throughout the negotiations, a key question has been whether states can regulate chemicals already undergoing a safety review by the EPA. While the government retains that sole power, Boxer and committee Chairman James M. Inhofe (R-Okla.) crafted a compromise to allow states to restrict a chemical’s use if a federal risk review and determination takes more than 3½ years.

If the EPA “is dragging its feet, states should be able to make decisions in their own interest,” said Richard Denison, the Environmental Defense Fund’s lead senior scientist. “I’ve been working on this for 15 years. It fixes every major problem with the current law.”

But the Maryland Public Interest Research Group contends that the bill’s time frame remains too long and is likely to stall efforts by states or green groups to block chemicals they consider unsafe.

“It’s really not a feasible way to protect Marylanders from chemicals while the EPA is assessing them,” said Juliana Bilowich, public health organizer for Maryland PIRG. “Some of these chemicals are acutely unsafe.”

The Environmental Working Group’s Scott Faber, the organization’s vice president for government affairs, said the EWG walked away from the bill because it represents “only a slight improvement” on “the worst environmental law in the books.”

The negotiations have involved high drama at times. The late Sen. Frank R. Lautenberg (D-N.J.) had worked with Inhofe on the issue starting in 2012, and brokered a compromise with Vitter shortly before Lautenberg’s death in 2013. Boxer had rejected that compromise as weak. Vitter and Udall, who pledged to carry on the effort during a private dinner after Lautenberg’s death, modified the measure significantly to attract broader support.

Boxer, who had criticized the original compromise during a flight with other senators to Lautenberg’s funeral, said Thursday, “I stopped this bill dead for years.” But she said she had been able to make critical changes in recent weeks. “I didn’t go on this bill. I changed this bill.”

Lautenberg’s widow has lobbied actively for the bill, which is named the Frank R. Lautenberg Chemical Safety for the 21st Century Act. Several senators said her involvement was crucial, with Inhofe calling Bonnie Lautenberg “the most important person in this whole process.”