Two senate bills intended to give an outdated toxic substances act a much-needed revision have stoked political fires about how the US should regulate chemicals.

Senators Barbara Boxer and Edward Markey introduced a bill on Thursday to reform the Toxic Substances Control Act (TSCA), just two days after senators David Vitter and Tom Udall introduced a different bill to reform the law, which hasn’t been updated since 1976.

Boxer and Markey’s alternate TSCA reform legislation calls for the US Environmental Protection Agency to review chemicals more quickly than it does now, use a stronger standard to judge chemical safety, and prioritize action on asbestos and chemicals that accumulate in human bodies and the environment.

“This bill will help ensure that communities are protected from chemical spills and clusters of disease that are related to toxic exposures,” Markey said in a statement.

Meanwhile, Vitter and Udall’s bill outlines a new process and deadlines for the EPA’s chemical reviews. It includes a schedule for EPA chemical reviews, but begins with just 25 chemicals – and each review could take up to seven years.

“Americans are exposed to a toxic soup of more than 80,000 different chemicals, but we have no idea what the impact of those chemicals is on our bodies – or those of our children,” said Udall, a Democrat from New Mexico, in a statement. “This bill represents the best opportunity to strengthen safeguards against dangerous chemicals and dramatically improve existing laws, while allowing innovation in the industry.”

While industry groups – including the American Chemistry Council, American Cleaning Institute and Toy Industry Association – largely welcomed Vitter and Udall’s bill, many environmental health advocacy groups oppose it. The Environmental Working Group, Breast Cancer Fund and Center for Environmental Health said the bill falls far short of what’s needed to protect the public from hazardous chemicals.

Meanwhile, a number of environmental advocates have welcomed the Boxer-Markey bill. “Senator Boxer’s proposal would be a clear win for public health and the environment,” said Andy Igrejas, director of Safer Chemicals, Healthy Families.

But the Environmental Defense Fund supports the Vitter-Udall bill. So does the American Chemistry Council, which said the bill “creates a cohesive, effective national chemical management system that will give consumers, retailers, manufacturers, public health advocates and regulators confidence that the chemicals in commerce are being used safely”.

Environmental Working Group executive director Heather White disagrees. The bill would do nothing to change the fact that TSCA does not require all chemicals be shown to be safe before they go to market, she said. It also wouldn’t compel the US Environmental Protection Agency, which administers TSCA, to evaluate the most hazardous chemicals – those that persist in the environment and build up in human bodies, she added.

“Our children are being born pre-polluted, with chemicals in their bodies,” White said. “This bill doesn’t require expedited investigation of these types of chemicals.”

One of the biggest problems with the Vitter-Udall bill, according to its critics, is that it would prevent the states from taking action on chemicals.

“This bill is the worst of both possible worlds,” said Environmental Health Strategies Center executive director Mike Belliveau, adding that it also won’t enable the EPA to act in a timely fashion.

Because the outdated TSCA has made it so difficult for the EPA to effectively restrict chemical use, individual US states have responded to consumer concern by passing their own chemical-regulation laws. To date, 35 different states have passed nearly 170 different bills to restrict use of hazardous chemicals. The proposed federal legislation would allow current state laws – passed before 2015 – to continue, but would restrict the creation of new state laws.

Exactly how the Vitter-Udall bill would work, if passed, is complicated. States would still be able to take action – restricting or banning a chemical – if the EPA doesn’t decide to review that chemical for possible restriction, but would no longer be able to do so once the EPA prioritizes that chemical for safety review.

Meanwhile, the Boxer-Markey bill would specifically retain state authority, allowing states to pass laws that are stricter than the federal laws. This is a growing issue given that two dozen US states are now considering roughly 85 new chemical-related bills.

As the battle of the bills rages on, it’s clear that the years-long TSCA reform debate is far from over.