On July 25, 2014 about 0740 mountain daylight time, a Cameron A-180 hot air balloon, N65059, made a hard landing near Questa, New Mexico. The pilot and 6 passengers were not injured; however, two additional passengers sustained serious injuries. The balloon was not damaged. The balloon was registered to and operated by the pilot as a 14 Code of Federal Regulations Part 91 flight. Visual meteorological conditions prevailed for the local flight which was being operated without a flight plan. The flight originated at Taos, New Mexico at 0700. The pilot reported that he was preparing to land the commercial balloon and was switching propane tanks to the burners when both burner pilot lights went out. The pilot tried to reignite a burner with the piezoelectric igniter, but when he pushed it in to generate a spark, the igniter failed to light the pilot light and the igniter button got stuck in the igniter sleeve. The pilot took out his strikers to relight the pilot light, but could not get it relit. At this point, the balloon was about 150 feet above the ground and the pilot prepared the passengers for a hard landing. The balloon struck the ground hard, skipped, and traveled about 30 feet before coming to rest. At 0735, the Routine Aviation Weather Report for the Taos Regional Airport, about 7 miles south of the accident site, was wind calm, 10 miles visibility, clear skies, temperature 62 degrees F, dew point 43 degrees F, and altimeter 30.36 inches of mercury. The balloon was equipped with a Cameron Balloons model CB2075-2 Ultra Double burner system. According to the manufacturer, the piezoelectric igniter in the system works on the same principle as an electric igniter on a gas grill; when you depress the button, the igniter produces a spark which will ignite any gas vapor present. A spring within the button pushes it back out of the sleeve after the igniter produces the spark. The piezoelectric igniter has an adjustment screw on the side of the sleeve to provide resistance on the button as it is depressed. If the adjustment screw is tightened too firmly, it can cause the button to stick in the igniter sleeve when actuated. The only time such an adjustment might be made is during an inspection of the burner. There are no specific tolerances for tightness on the adjustment screw. As for why the pilot's attempt to relight the pilot lights using his manual strikers was unsuccessful, the manufacturer stated that depending on how the pilot had the burner gimbaled it could have allowed airflow across the burner in a way that prevented the relight from occurring.