On May 6, 1937, the Hindenburg, a German zeppelin airship, burst into flames when it tried to dock in New Jersey after a transatlantic flight. The vessel was destroyed within seconds, and 36 people were killed.
The Hindenburg was kept aloft by hydrogen, a highly flammable gas. Helium would have been the safer alternative (in fact, such airships were designed to use helium), but the Americans, who had a monopoly on its distribution, limited exports to Nazi Germany under the 1927 Helium Control Act.