Transportation Secretary Pete Buttigieg visited East Palestine, Ohio, on Thursday to tour the site where a train wrecked nearly three weeks ago as the government faces growing criticism over the federal response to the derailment.

The Feb. 3 derailment led to evacuations and fears of air and water contamination after a controlled burn of toxic chemicals aimed at preventing an explosion.

The Biden White House has defended its response to the derailment, saying officials from the Environmental Protection Agency, National Transportation Safety Board and other agencies were at the rural site within hours of the derailment. The White House says it has also offered federal assistance and FEMA has been coordinating with the state emergency operations center and other partners.

Buttigieg has faced criticism for not visiting the site earlier, including from former President Donald Trump, who came to Ohio on Wednesday. The Department of Transportation said Buttigieg is visiting now that the U.S. Environmental Protection Agency declared the emergency phase of the crash to be over and the start of long-term cleanup efforts is underway.

The NTSB was expected to release a preliminary report later Thursday on the derailment.

More than three dozen freight cars — including 11 carrying hazardous materials — derailed on the East Palestine outskirts, near the Pennsylvania state line, prompting an evacuation as fears grew about a potential explosion of smoldering wreckage.

Officials seeking to avoid an uncontrolled blast intentionally released and burned toxic vinyl chloride from five rail cars, sending flames and black smoke high into the sky. That left people questioning the potential health effects even as authorities maintained they were doing their best to protect people.

As remediation of the site continued, Norfolk Southern announced late Wednesday it had agreed to excavate the soil under two tracks. Ohio Gov. Mike DeWine had called out the railroad company’s failure to address the contaminated soil underneath its tracks before repairing them and running freight again.

“Our original plan would have effectively and safely remediated the soil under our tracks. As I listened to community members over the past two weeks, they shared with me their concerns about that approach. I appreciate the direct feedback, and I am addressing it,” Norfolk Southern President and CEO Alan H. Shaw said in a written statement.

(AP)