The governor of Ohio told residents living near the site of a toxic train derailment that it was "safe" to drink the water, as authorities investigate potential environmental fallout from the accident earlier this month.

The cargo train derailment sparked a massive fire and triggered the release of toxic fumes, including from vinyl chloride, a colorless gas deemed carcinogenic by the US National Cancer Institute.

Earlier Wednesday Ohio Governor Mike DeWine told CNN that while air quality in the town of East Palestine where the wreck occurred was "safe," residents should not yet drink the water out of an abundance of caution.

"We did get a test back late yesterday of the water in the village and the first well that we tested, the water was fine," he told the broadcaster, urging people to nonetheless "use bottled water. Don't take a chance."

On Wednesday evening he tweeted to say that new tests showed "no detection of contaminants in East Palestine's municipal water system. With these test results, @OhioEPA is confident that the municipal water is safe to drink."

Earlier, Environmental Protection Agency Administrator Michael Regan, who was set to travel to the affected area Thursday, told CNN that his agency would be able to give the public more information "as the conditions on the ground become safe."

He said that scientists and engineers would not be put "in harm's way."

The Norfolk Southern train with 150 cars was shipping cargo from Madison, Illinois to Conway, Pennsylvania when it derailed on February 3. The accident site is along the border between Ohio and Pennsylvania.

The accident resulted in the derailment of 38 cars, after which "a fire ensued which damaged an additional 12 cars," the National Transportation Safety Board said in a statement Tuesday.

Of the derailed cars, 11 were carrying hazardous materials, including vinyl chloride, butyl acrylate and other chemicals, the NTSB said.

Several thousand residents were evacuated as authorities assessed the danger.

To avert explosion, the railroad conducted a controlled release of the chemicals, which discharged toxic and potentially deadly fumes into the air, DeWine's office said.

- 'Very toxic materials' -


Five days after the derailment, evacuated residents were allowed to "safely return home," the governor's office said, adding that there would be ongoing air monitoring in the area.

But one week after the accident the EPA reported that the chemicals involved in the wreck were "known to have been and continue to be released to the air, surface soils, and surface waters."

Some 3,500 fish died along 7.5 miles (12 kilometers) of nearby streams, the Ohio Department of Natural Resources reported.

DeWine said Norfolk Southern would be held accountable and should "pay for everything," adding that some people in East Palestine were concerned the company would leave before the cleanup is finished.

"They are responsible for a very serious train wreck that occurred with some very toxic material," he told CNN. "So we're going to hold their feet to the fire."

Norfolk Southern said in a statement Wednesday it had provided $1.5 million to families and businesses for "costs related to the evacuation."