On May 25, 2000, about 0845 mountain daylight time, a Sikorsky S-58, N2253A, registered to and operated by Thomas Helicopters as a 14 CFR Part 137 aerial application flight, collided with power wires near Buhl, Idaho. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft was destroyed by a post-crash fire. The commercial pilot, the sole occupant, was seriously injured. The flight originated from a staging area about five minutes prior to the accident. In a written statement, the pilot reported that he had just taken off from the staging area with 320 gallons of a diluted water mixture that contained 6.25 gallons of a concentrate mixture of Di-Syston 8. The pilot was flying the same flight path to the field as the flight before. This was about the sixth load of the day. The pilot reported that along this flight path, he had to fly over some television and radio antennas, and two sets of power lines. The power lines were the last obstacles along the flight path. The pilot reported that prior to crossing the power lines, he was distracted by a radio call from another pilot. The pilot looked down at a map to verify a field location, and when he looked back up, he did not see anything unusual. The helicopter then collided with the power lines that were the last known obstacles along the flight path. The power lines were approximately 75-100 feet above ground level. After the collision, the helicopter pitched nearly straight up, leveled slightly, then fell to the ground in a tail low attitude. A post-crash fire consumed the helicopter. The pilot reported that just prior to the collision there were water drops on the windshield, which was dirty, and the sky was overcast, reducing his visibility substantially.