The railroad company at fault for the East Palestine train derailment, Norfolk Southern, has been told to stand down on future toxic waste shipments from the crash site in East Palestine by the government’s highest environmental authority.

According to NPR, the Environmental Protection Agency (EPA) has told Norfolk Southern they will not be transporting any more toxic materials from the site “until federal officials could review the routes and disposal facilities.”

The weekend announcement came just days after the EPA announced it was assuming control of the cleanup efforts in East Palestine following the train derailment earlier this month, which resulted in the release of hazardous chemicals into the soil and air and prompted health and safety concerns from residents in the town and nearby.

“We have instructed Norfolk Southern to pause but only temporarily,” [EPA regional administrator Debra] Shore said, adding that officials would resume transporting the contaminated waste to approved disposal sites “very soon.”

“Moving forward, waste disposal plans, including disposal location and transportation routes for contaminated waste, will be subject to federal EPA review and approval,” she noted.

The railroad company has come under a lot of fire in recent weeks over the crash, which spilled toxic chemicals in the small Ohio town, prompting an environmental crisis and forcing the evacuation of the town. The National Transportation Safety Board blasted Norfolk Southen in its most recent report on the crash.

The NTSB report found that one of the train’s cars carrying plastic pellets was heated by a hot axle that sparked the initial fire, according to Jennifer Homendy, the chair of the safety board. As the temperature of the bearing got hotter, the train passed by two wayside defect detectors that did not trigger an audible alarm message because the heat threshold was not met at that point, Homendy explained. Athird detector eventually picked up the high temperature, but it was already too late by then.

“This was 100% preventable. … There is no accident. Every single event that we investigate is preventable,” Homendy said during a news conference Thursday. “The NTSB has one goal, and that is safety and ensuring that this never happens again.”

Currently, roughly 102,000 gallons of liquid waste and 4,500 cubic yards of solid waste are being stored in East Palestine right now. Another five truckloads of contaminated soil originally sent to Michigan were returned to the town, according to Ohio governor Mike DeWine’s office.

In a statement to NPR, the rail company said “we are working with the US EPA to resume removing waste from East Palestine as soon as possible.”

The transportation of chemicals away from East Palestine sparked even more controversy as Norfolk Southern began re-routing some of the reclaimed spill to Texas and Michigan. Michigan lawmakers reported that they received no head’s up about the incoming contaminated waste.