The Environmental Protection Agency waited a month to consult some of its top experts about the risk of dangerous chemical exposure around East Palestine, Ohio, following the fiery derailment of a Norfolk Southern train hauling toxic materials, internal emails show.

That delay left at least two EPA scientists surprised and concerned. And it occurred while the agency was deferring to the railroad giant and its web of contractors to spearhead environmental testing, including crafting protocols for sampling soil, water and air for chemicals a move many saw as a glaring conflict of interest.

HuffPost obtained internal agency communications via a Freedom of Information Act request. Paul Van Osdol , a reporter at WTAE TV in Pittsburgh, Pennsylvania, first reported some of the documents.

The Norfolk Southern train derailed in East Palestine on Feb. 3 while hauling toxic and flammable materials, including hundreds of thousands of pounds of vinyl chloride, a common organic chemical used in the production of plastics and thats been linked to several types of cancer .

The wreckage burned for several days, and on Feb. 5, authorities ordered an urgent evacuation for everyone within one mile of the site due to the risk of what they described as a catastrophic tanker failure which could cause an explosion with the potential of deadly shrapnel traveling up to a mile. To prevent such an explosion, the local fire chief, Norfolk Southern and other state and local officials conducted what they called a controlled vent and burn of the vinyl chloride on Feb. 6, three days after the crash, sending plumes of thick black smoke billowing into neighboring communities.