The private pilot, who was acting as the pilot-in-command, stated that shortly after he descended the airplane and leveled off at 6,000 feet mean sea level (msl) the engine sputtered and lost power. Attempts to restart the engine was unsuccessful. The pilot subsequently executed a forced landing into a cement mixing yard, shearing off the landing gear in the process and substantially damaging the fuselage and wings. The certified flight instructor (CFI), who was acting as copilot, stated that sunset occurred about 1 hour into the flight. The local sunset time was approximately 1627. The accident occurred at 2038, which established the total time airborne about 5 hours. Both pilots stated that the airplane was fully fueled before departing, and airport fueling records show that 19.6 gallons of fuel was purchased by the CFI. The Cessna 150 Pilot Operating Handbook (POH) states that an airplane equipped with standard fuel tanks has 22.5 gallons of usable fuel, and has about 5 hours of endurance at cruise power. First responders reported that there was no fuel observed in the airplane's fuel tanks and no odor of fuel was observed at the accident site. A postaccident examination of the airplane concluded that no engine mechanical malfunction or failure was identified that would have precluded normal operation.