Request mutual aid be put on standby from nearby town that is 1 hour away. Reverse 9-1-1 area residents and ask them to stay home and shelter in place. Place a similar broadcast over the local FM radio station. Have the LEO's close off the roads to the fair and shut it down. Detail a posse pilot to overfly crash site if possible. Send fire dept. to stage upwind of the plane crash to deal with potential leak. Ask hospital and EMS to be on standby for contaminated casualties. Assign a ham radio operator to the command post and one to the hospital as backup communications. Decontaminate fire crews at truck wash as they return.