INDUSTRIAL CHEMICALS are in countless products, but the government’s system to ensure they are safe is broken, and has been for decades. The past few years showed why fixing it has been so hard: As some members of Congress attempted to negotiate bipartisan reforms, others made the perfect — or the perfectly political — the enemy of the good.

This impasse looks as though it’s about to end, at long last, as Congress considers a bipartisan chemical safety reform bill this week. On its merits, the Frank R. Lautenberg Chemical Safety for the 21st Century Act should pass by acclamation.

Under current law, the Environmental Protection Agency is hobbled in all sorts of dangerous ways. The agency cannot subject chemicals to safety testing without evidence that they are potentially risky — which is hard to obtain without testing. Consequently, the EPA has managed to examine a mere 200 chemicals since 1976, though thousands are produced and sold every year.

The bill would subject all chemicals already on the market to some level of review, with the EPA prioritizing the chemicals it sees as the riskiest — formaldehyde and flame retardants would probably make the list. Chemical manufacturers could ask the agency to analyze a chemical out of turn, as long as they fund the review. The EPA would have to find new chemicals safe before they entered the market, and the agency would have more power to order testing. If the EPA found that a chemical posed an unreasonable risk, its options would range from added warnings to outright bans.

This would be a massive improvement on the status quo. But opposition has crystallized over the role of states, some of which, such as California, have imposed tough chemical regulations in the absence of strong federal rules. The bill would allow existing state regulations to stay on the books. But going forward, federal action would preempt state efforts to impose new restrictions. This would keep the rules generally consistent from state to state, but some activists and members of Congress want maximum latitude for states to regulate as they choose.

If the critics prevail, they will kill a good bill. The legislation would significantly improve chemical rules for every American and prevent an increasingly expensive and inconsistent patchwork of regulations. It would give states flexibility to request a waiver from the EPA to avoid federal preemption if they have good reason to impose state-level rules. Over the past few weeks, the bill’s negotiators have adjusted several portions of the bill to make them more acceptable to the critics. If there is any naysaying when it comes up for its final vote, it should be little more than token opposition.