On June 19, 1993, at approximately 2030 hours mountain daylight time (MDT), a Bell 206B, N33EA, registered to Rotorcraft Partnerships Ltd., and being operated/flown by Ray E. Burney, a certificated commercial pilot, was substantially damaged during an in-flight collision with terrain following a complete power loss while beginning a spray run of chemical over an agricultural field approximately 18 miles south of Harlem, Montana. The pilot, who was ejected from the aircraft during the impact, sustained minor injuries. Visual meteorological conditions prevailed and no flight plan had been filed. The flight, which was for the purpose of chemical dispersion over an agricultural field, was to have been operated in accordance with the requirements set forth in 14CFR137, and originated from a staging point near the accident site. Following the accident, the pilot reported to the investigator in charge that the aircraft was fueled using all the remaining fuel (25 gallons) from the on site fuel truck. The helicopter was serviced with herbicide and then departed for its destination spray site one mile distant. As the helicopter descended to approximately six to ten feet above ground at a speed of 60 to 70 miles per hour, the engine ceased operating. The pilot reported that he attempted to execute a "quick stop" but collided with terrain during which he was thrown out of the aircraft. Post crash on site examination of the wreckage as well as the fuel truck and FBO fuel supplier by FAA inspector James Binion revealed the following: 1) The FBO fuel tanks were checked for water and found free of water. 2) The fuel truck was checked taking a sample from the truck's low point drain. Only a small amount of water was evident with the majority being fuel. 3) Approximately 350 milliliters of fluid was removed from the pressure side of the aircraft's airframe fuel filter and system subsequent to the accident. More than 20% of the fluid (75 milliliters) tested positive using water sensitive paste (refer to photographs 1 and 2). Additionally, the aircraft was defueled by its owner subsequent to salvage. A total of 2.5 gallons of water was recovered from the fuel tank out of an approximate total of 40 gallons of fuel (refer to attached letter of Ken Trovato).