Donald Trump’s record of rolling back environmental protections was highlighted by critics on Wednesday as the ex-president visited the town of East Palestine, Ohio, and called the federal response to the toxic train derailment there earlier this month a “betrayal” .

Trump’s administration, which rolled back more than 100 environmental rules in total, watered down several regulations at the behest of the rail industry.

He withdrew an Obama-era plan to require faster brakes on trains carrying highly flammable materials, shelved a rule that demanded at least two crew members on freight trains and dropped a ban on transporting liquified natural gas by rail, despite fears this could cause explosions.

“His trip serves as a reminder that Trump and his administration made gutting transportation and environmental safety regulations a key priority of their Maga agenda,” the Democratic National Committee said in an email to reporters.

Linking to a number of media reports of his transportation policies, it said, “Trump and his administration rolled back … transportation safety and environmental rules, including toxic chemical regulations,” and “Trump’s budget proposals slashed funding for investigating accidents, enforcing environmental rules, and prosecuting environmental crimes”.

“I don’t know exactly what he’s planning to do there, especially since his administration was anti-regulation and pro-industry every step of the way,” Pete Buttigieg, the transportation secretary, told CBS the day before Trump’s visit.

Buttigieg has been attacked by Republicans for failing so far to visit the site of the Ohio disaster, and the Department of Transportation said on Wednesday that he will visit the town on Thursday. The statement said: “As the secretary said, he would go when it is appropriate and wouldn’t detract from the emergency response efforts. The secretary is going now that the Environmental Protection Agency (EPA) has said it is moving out of the emergency response phase and transitioning to the long-term remediation phase.”

The head of the National Transportation Safety Board – the lead agency investigating the crash – has said that the improved braking system wouldn’t have applied to the train that veered off its tracks in East Palestine, but environmental groups are pushing for the Biden administration to reinstate the rule anyway.

There has been pressure from some Republicans to review safety rules, with Mike DeWine, the Ohio governor, saying it is “absurd” that the train could be marked as non-hazardous because it wasn’t exclusively carrying toxic material. But many other GOP figures have so far shied away from calling for tighter regulation of the rail industry, instead focusing on what they say has been a ponderous response from the Biden administration.

Residents have expressed distrust at official statements that the water and air in the town is safe. In his visit on Wednesday, Trump, who is running for the White House again in 2024, said the community needs “answers and results”, not excuses. He spoke at a firehouse roughly half a mile from where more than three dozen freight cars – including 11 carrying hazardous materials – came off the tracks near the Pennsylvania state line.

“In too many cases, your goodness and perseverance were met with indifference and betrayal,” Trump said. He appeared with Senator JD Vance, Mayor Trent Conaway and other state and local leaders.

The former president and other Republicans have intensified criticism of the Biden administration’s handling of the 3 February derailment, which led to evacuations and fears of air and water contamination after a controlled burning of toxic chemicals aboard the rail cars.

The Biden White House has defended its response to the derailment, saying officials from the EPA, National Transportation Safety Board and other agencies were at the rural site within hours of the derailment. The White House says it has also offered federal assistance and that the Federal Emergency Management Agency has been coordinating with the state emergency operations center and other partners.

EPA administrator Michael Regan visited the site last week and earlier this week and tried to reassure skeptical residents of the town, which has a population of around 5,000, that the water was fit for drinking and the air safe to breathe.

“I’m asking they trust the government,” Regan said. “I know that’s hard. We know there’s a lack of trust.” Officials are “testing for everything that was on that train”, he said.

The Associated Press contributed reporting