The Hindenburg’s fiery crash in 1937 was a historic event, but there was some mystery as to what caused the explosion. There has also been plenty of speculation as to how the dirigible caught fire so quickly, and some of those theories were featured on a “Mythbusters” episode, but scientists now claim they have solved the mystery of what caused the Hindenburg explosion.

According to researchers at San Antonio's South West Research Institute, static electricity led to the fatal spark, the (UK) Independent reported. As the airship was about to land in Lakehurst, N.J., the Hindenburg exploded into flames, killing 35 people onboard. Jem Stansfield, a British aeronautical engineer, led the research and the team exploded several scale model replicas of the Hindenburg to test out several popular theories.

Much like in the Discovery channel's “Mythbusters,” Stansfield and his team tested out theories, such as a bomb being aboard the ship or the ship’s skin as the cause of the explosion, and came to the conclusion that static electricity was to blame. The research also revealed several factors that led to the Hindenburg explosion.

The Hindenburg was leaking hydrogen and passed through an electrical storm, which led to the airship being charged with static electricity, notes the Independent. Hydrogen gas leaked into the Hindenburg’s ventilation shafts, it remains unclear how, but as the crew was tethering the ship, they essentially “grounded” the airship, causing the stored static electricity to discharge and ignite the hydrogen that led to the explosion. Speaking to the Independent, Dan Grossman, an airship historian, said, “I think you had massive distribution of hydrogen throughout the aft half of the ship; you had an ignition source pull down into the ship, and that whole back portion of the ship went up almost at once.”

The research is part of a documentary that will air on the UK’s Channel 4 on Thursday. A video of the 1937 Hindenburg explosion can be viewed below.

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