For nearly six hours last week, members of the U.S. Senate’s Environment and Public Works Committee gathered to hear comments about a bill that could overhaul the EPA’s ability to regulate toxic chemicals.

Hailed by a panelist from West Virginia as “the best, perhaps last, chance to reform” the Toxic Substances Control Act (TSCA), the new Chemical Safety Improvement Act (CSIA) is the first such proposal to have won bipartisan support since the original law passed in 1976—and thus has a chance at becoming law.

However, critics say that, as currently drafted, the CSIA could actually be detrimental to the cause of regulating toxins.

California Attorney General Kamala Harris joined the attorneys general from eight other states to submit a letter on July 31 to the Senate committee, raising concerns that the new bill will make it impossible for states to continue regulating chemicals themselves. They worry that existing regulations could become null and that future EPA designations might not be as strong as individual states might like, if the CSIA is passed.

For instance, Oregon currently limits the presence of certain chemicals in arts-and-crafts supplies. Similarly, Washington has banned plastic bottles and cups that contain BPA and restricts the amount of lead, cadmium and phthalates in children’s products. The states’ attorneys general are concerned the CSIA would override those regulations.

Currently, the EPA regulates toxic chemicals under the TSCA, which is, by all accounts, deeply flawed. Though the law is the strongest federal piece of legislation guiding oversight of chemicals, it severely limits the EPA’s ability to test new chemicals on the market or even regulate known toxins. TSCA’s extreme limitations were highlighted in 1991, when an EPA ban on asbestos was overturned by a circuit court. The ruling maintained the EPA’s regulation on new uses of asbestos in the market, but allowed existing uses to remain unregulated.

For years, lawmakers, health advocates and watchdog groups have sought ways to give the EPA more latitude in regulating chemicals in the environment and consumer products. In 2011, the EPA made some headway against the TSCA’s provision that allowed manufacturers to keep chemical formulas private as trade secrets. In the absence of adequate federal regulations, several states have taken the oversight of toxins into their own hands.

In 1986, California determined that its citizens had a right to know about the chemical toxins in the environment around them and in products they brought into their homes. The state enacted a law, the Safe Drinking Water and Toxic Enforcement Act of 1986, more commonly known as Proposition 65. The law requires companies to label products containing any of the roughly 800 toxic chemicals listed in the bill. Rather than list, many manufacturers chose to change the formulations of their products to comply with legal limits.

Sen. David Vitter (R-Louisiana), who co-sponsored the CSIA with the late Sen. Frank Lautenberg (D-New Jersey) in May, recognized the states’ concern in his opening statements at the hearing. However, he indicated that those were either “misimpressions or willful distortions” of the bill. “In no way did we intent to remove the authority of any state to protect their water, air or citizens,” he said.

Still, he agreed that the wording would be clarified to “make that even more crystal clear.”

There is widespread agreement that the TSCA is desperately in need of reform, but what shape that should take, and how far reform should go, is far from settled. The proposed CSIA does, in fact, move to fix some of TSCA’s major failings: giving the EPA more latitude to require testing for new chemicals, providing more public information about potential exposure, and giving the EPA broader abilities to ban chemicals that do not meet safety standards. Proponents say the new bill will shift the burden of proof from the EPA and onto industry, making it far easier for the EPA to require testing.

Still, the bill’s opponents say it does not go far enough. Among the complaints are concerns that it doesn’t outline any deadlines for reforms, doesn’t include specific language for protecting vulnerable populations, and would be inefficient, tying up the EPA with redundant requirements.

In closing the hearing on July 31, Chairwoman Barbara Boxer of California looked at Nancy Buermeyer of the Breast Cancer Fund and asked if the fund thought that the CSIA is better than current law. Buermeyer replied frankly, “We think, all told, this bill actually takes us a step back.”

“I can’t ignore that,” Sen. Boxer responded.

While some warn that moving too far from the current proposal could upset the bipartisan support, members of the Senate and the morning’s panelists agreed to continue working to draft suitable language.

“This means we have a lot of work to do,” Sen. Boxer said, “and I am ready to do it.”

Katie Mast is an editorial intern at High Country News, the site from which this was cross-posted. The author is solely responsible for the content.