See this Fox News report: “White House explains why it turned down disaster relief for Ohio.”
Let me run through what “hypothetically” might have happened there in Ohio. The governor of Ohio, or one of his senior staff, asks the Ohio state emergency management director if they can/should ask for a Presidentially Declared Disaster for the train derailment. Ohio emergency management goes back to the policy level and tells them, “We don’t think so for this type of incident that is really an ‘emergency’ and not a ‘disaster’ based on the size and scope of what has happened.” The policy level persists and tells Ohio emergency management to prepare a request for the governor to sign.
Why send the letter/request if you don’t think it qualifies? Because it shows that “you are doing everything possible” to help your citizens and you have left “no stone unturned” to find them help.
Back in Ohio, we know the Norfolk Southern Railway is who is “on the hook” for the spill, the cleanup, the impact to people and their property, along with long-term health impacts.