On August 17, 2008, at approximately 0830 central daylight time, a Balloon Works, Firefly 7-15, N90897 balloon, piloted by a private individual, was destroyed when the balloon's envelope caught fire during a tethered accent near Mountain Grove, Missouri. The non-certificated pilot, sole occupant of the balloon, was fatally injured. Another individual was seriously injured while assisting the pilot, after a propane tank exploded. Visual meteorological conditions prevailed, and no flight plan was filed for the 14 Code Federal Regulations (CFR) part 91 flight. Several ground handlers reported that they and the balloon pilot was going to honor the balloon's owner, who had recently passed away, by making a tethered balloon flight. During the accent, a propane leak occurred with a subsequent fire; the pilot was not able to put out the fire. The fire caused one of the propane tanks to explode. At about 80 feet in the air, the pilot jumped from the burning craft to escape the fire. The balloon's basket then separated from the envelope and landed near the pilot. When ground handlers went to aid the pilot, a second propane tank exploded, causing serious burn injuries to one of the participants. The reason for the propane leak was not determined.