On February 3, the derailment in the locality of East Palestine, Ohio, caused a huge fire and the evacuation of hundreds of people.
Among other things, the train was carrying vinyl chloride, a carcinogenic and highly flammable chemical used in the manufacture of plastic.
The railway authorities had carried out "controlled" releases of vinyl chloride to avoid a possible explosion, releasing toxic fumes.
The United States Environmental Protection Agency (EPA) announced in a press release that it had asked the company Norfolk Southern to "clean up contaminated soil and water resources" and to "reimburse the EPA for cleaning services that will be offered to residents and businesses in order to reassure them more.
This is a binding order, according to the EPA.
The agency said it would approve a plan detailing "all necessary measures to clean up the environmental damage caused by the derailment".
"If the company fails to carry out the actions ordered by the EPA, the Agency will intervene immediately, do the necessary work and then seek to compel Norfolk Southern to pay triple the cost," the EPA said.
"Let's be clear: Norfolk Southern will pay to clean up the mess it has created and the trauma it has inflicted on this population," EPA Chief Michael Regan said in the statement.
President Joe Biden's administration scrambled to provide reassurance after the derailment as residents expressed anger and concern over the pollution and potential health consequences.
Some have reported to the media that they had had various symptoms, including headaches, and said they feared they would end up with cancer in a few years.
About 3,500 fish also died in the surrounding waterways, according to the local natural resources agency.
Authorities have said the air is "safe" and tests of water from the municipal system have detected no pollutants, but residents are skeptical and some have already filed complaints against the rail company.
© 2023 AFP