For nearly a decade, lawmakers and railroad regulators have been trying to get puncture-susceptible tank cars, designed in the 1960s for nonhazardous shipments, off the nation’s tracks. In the wake of the catastrophic derailment and chemical release in East Palestine, Ohio, in February, bipartisan rail safety legislation committed to quickly ending hazardous material shipments in the antiquated tank cars, which regulators said had failed at higher rates during the Ohio derailment than updated, fortified tank cars on the same train.

“The Railway Safety Act would require the adoption of safer tank cars that carry hazardous materials by 2025, instead of 2029 — something we’ve called on Congress to get done,” Transportation Secretary Pete Buttigieg tweeted when the bill was introduced.

But last month, the bill’s cosponsor, Ohio Republican senator J. D. Vance, quietly amended his own legislation to delay the tank car change by years, at the request of rail and chemical industry lobbyists. According to lobbyists’ Senate testimony, manufacturers would have been unable to comply with the faster timeline — even though one of the lobbying group’s members has previously said manufacturers could build and retrofit tank cars on this production schedule.