EAST PALESTINE, Ohio — United States officials on Thursday sought to reassure an increasingly nervous public of the government's commitment following a train derailment that resulted in the release of toxic chemicals in the soil, air and water in Ohio.

But the accident is continuing to raise questions and fuel public distrust of authorities.

No traces of vinyl chloride, a colorless carcinogenic gas, nor hydrogen chloride were detected after examining more than 480 homes in the area of the crash, alleged Michael Regan, administrator of the US Environmental Protection Agency.

"I want this community to know that they don't have to manage this issue on their own. We will be here to help," Regan said while visiting the town of East Palestine, where the accident occurred.

The Norfolk Southern cargo train derailment on Feb 3 sparked a massive fire. To avert explosion, the railroad conducted a "controlled release" of the chemicals, which discharged toxic and potentially deadly fumes into the air, the governor's office said.

"We're going to get to the bottom of this," White House press secretary Karine Jean-Pierre told reporters at a briefing. "We're going to hold Norfolk Southern accountable."

Hundreds of evacuated residents have been allowed to return home, but many have voiced alarm over health issues, with some reporting headaches and stating that they fear they may end up with cancer.

Meanwhile, some 3,500 fish died along 12 kilometers of nearby streams, the Ohio Department of Natural Resources reported.

Authorities said tests show that the air is safe and no pollutants are being detected in the municipal water system.

However, those who get water from private wells should continue to use bottled water until their wells are tested, they said.

One resident told local TV station WKYC that people were "suspicious, paranoid and worried".

Another, Kelly Felger, told CNN: "I'm scared. I'm scared for my family, I'm scared for my town."

Jenna Giannios of Boardman, a town near East Palestine, told NBC that she has been drinking bottled water and is uncomfortable bathing in tap water from the bathroom.

"I'm concerned with the long-term health impact," Giannios said. "It's just a mess."

Residents voiced similar concerns at a community meeting on Wednesday night, with Regan and East Palestine Mayor Trent Conaway in attendance.