One year after a fiery train derailment spilled thousands of gallons of toxic chemicals in East Palestine, Ohio, President Biden will travel there on Friday and face a politically divided community anxious over the long-term health consequences of an environmental catastrophe.

Mr. Biden, who promised to visit soon after the disaster, has faced criticism from Republicans and some residents for not going sooner. In a sign of how politically fraught the situation has become, Trump supporters planned a rally to coincide with Mr. Biden’s visit.

“The town is still very divided,” said Misti Allison, a 35-year-old resident of East Palestine, a small town in a conservative state. She said some people hoped that Mr. Biden’s visit would bring the kind of relief many people wanted, such as health screenings far into the future.

“Some people say it’s too little, too late,” she said. “You should’ve been here February of last year, not February of this year.”

Mr. Biden is expected to give remarks on Friday detailing his administration’s effort to help residents of East Palestine, as well as outline measures to hold accountable Norfolk Southern, the operator of the freight train carrying the toxic chemicals.

The White House has said the government has sent a steady flow of federal resources to the community and deployed hundreds of people to assess the risks in the days after the spill. Some members of the community, many of whom have said they are suffering from health problems, say Mr. Biden should issue a disaster declaration, which would allow the state to tap into even more federal resources.