Hundreds of irate residents of the Ohio town where a train derailed and spilled toxic chemicals have packed into a high school gym, seeking answers to what health dangers they face.

East Palestine Mayor Trent Conaway, looking angry and tired, said at Wednesday’s town hall that he wanted to help provide some reassurance for the 4700 citizens of his town, and hold to account those responsible for the train derailment.

“We need our citizens to feel safe in their own homes,” Mayor Conaway said. “I need help. I’m not ready for this. But I’m not leaving, I’m not going anywhere.”

Mayor Conaway said Norfolk Southern, which operated the toxins-laden train that derailed on February 3 in East Palestine, was working closely with him.

“They screwed up our town. They’re going to fix it,” he said.

Norfolk Southern officials did not attend the meeting, saying they feared violence following concerns about “the growing physical threat to our employees and members of the community”.

The Norfolk Southern Railroad-operated train’s derailment caused a fire that sent a cloud of smoke over East Palestine.

Thousands of residents were forced to leave. After railroad crews drained and burned off a toxic chemical from five tanker cars, residents were allowed to return to their homes on February 8.

Much remains unknown of the dangers posed to residents by the toxins that spilled, experts said.

Many in the area have complained of headaches and irritated eyes, and noted that chickens, fish and other wildlife have died off.

Despite that, state health officials have insisted to residents that East Palestine is a safe place to be.

Erik Olson, the senior strategic director for health and food at the Natural Resources Defense Council, a non-profit group focused on the environment and public health, said the unknown dangers stemming from the derailment vastly outweighed reassurances from officials.

“This is clearly a very toxic brew of chemicals,” Mr Olson said.

The air and water testing that had been done so far seemed limited and “is not all that reassuring”, he said.

Mr Olson said much more needed to be understood about how much the soil and groundwater was polluted, which posed a greater longer-term danger than air pollution.

Ohio officials have said that a plume of pollution in the Ohio River is moving at 1.6km/h. But they say cities in the plume’s path can turn off their drinking water intakes as it floats by.

They’ve also said that drinking water tests have not raised concerns and normal water treatment would remove any contaminants.

Gerald Poje, a toxicologist and a former founding member of the Chemical Safety Board, a federal agency, said it could take months or years before the scale of the damage was fully known.

“This is a terrible tragedy in Ohio,” Mr Poje said.

“There is a long challenge ahead of everybody into how to discern risks that are unknown at this moment in time.”

-Reuters