On April 22, 1994, about 1840 hours eastern daylight time, N76545, a Cessna 140, operated by the owner/pilot, was substantially damaged during takeoff from the Clarion County Airport, Clarion, Pennsylvania. The certificated private pilot received minor injuries, and the sole passenger was seriously injured. Visual meteorological conditions prevailed and a flight plan was not filed. The local flight was conducted under 14 CFR 91. A witness observed the pilot conduct a pre-flight inspection, taxi to the end of runway 6, and perform an engine run-up. The airplane was then observed to begin its takeoff roll. About 500 feet down the runway, the tail of the airplane began to rise. The airplane was then observed to swerve off the left side of the runway and down an embankment. The airplane nosed over and was found upside down about 60 feet from the left edge of runway. The pilot stated that as he added full power and began the takeoff roll, the airplane began to drift to the left. He "overcontrolled" the airplane with right rudder and the airplane began to veer to the right. He attempted to regain directional control, but was unable. He stated that "... a ground loop was inevitable ..." so he closed the throttle, lowered the flaps, and observed the airplane veer off the left side of the runway and down an embankment. The pilot did not report any mechanical malfunctions. According to an FAA Aviation Safety Inspector, the airplane was found inverted at the base of an embankment that borders the north side of the runway. The airplane came to rest about 1,000 feet from the approach end of runway 6. Both wings and the vertical stabilizer were substantially damaged. Tire skid marks consistent with witness observations were found on the runway. An examination of the airplane did not reveal any pre-impact mechanical deficiencies.