Luckily, the crew on board UPS flight 1307 escaped with only minor injuries. In the accident investigation, NTSB officials have concluded that lithium batteries and a flammable liquid were in the cargo hold, but have not yet determined the exact cause of the fire. The investigation is expected to take several more months to complete.

The NTSB held separate public hearings about the fire on July 12 and 13th. The hearings didn't focus on whether the batteries were the cause of the fire, but rather how batteries are made and how they can fail.

FAA official William Wilkening testified that there have been 60 incidents since 1991 that involved batteries catching on fire, smoking or getting hot. According to Wilkening, most of the batteries were lithium or lithium-ion. He added that in the past ten years the FAA has given 49 fines totaling $517,000 for improper packaging of lithium batteries. Harry Webster with the FAA Technical Center testified that lithium-ion batteries could vent flammable liquid and "pose a risk to the cargo compartment."