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