The iconic German commercial passenger-carrying Luftschiff Zeppelin #129 (LZ 129) also known as the Hindenburg was the lead ship of the Hindenburg class and also the longest class of flying machine and the largest airship by envelope volume. Built and designed by the German Zeppelin Company in Friedrichshafen. It flew from March 1936 until it was destroyed by fire on May 6th, 1937, at the end of a North American transatlantic journey.
But even though the Hindenburg was inflated with 7 million cubic feet of highly flammable hydrogen gas, it had a special smoking room! But there were quite a few safety measures in place: for example the room was kept at a higher pressure than the rest of the ship, so no leaking hydrogen could possibly enter, as well as a separating double-door airlock to the rest of the passenger section. There was also always a member of the zeppelin’s staff monitoring the smoking room and there was only one electric lighter provided; no lighter, matches or any other open flames were allowed aboard the airship.
You can read more about the smoking room and find some pictures of it on airships.net.
If this room had any involvment in the fire is unknown but very unlikely. What really caused the fire is subject to debate; this is a small excerpt of the Hindenburg disaster from wikipedia:
The Hindenburg’s arrival on May 6 was delayed for several hours to avoid a line of thunderstorms passing over Lakehurst, but around 7:00 pm the airship was cleared for its final approach to the Naval Air Station, which it made at an altitude of 650 ft (200 m) with Captain Max Pruss at the helm. Four minutes after ground handlers grabbed hold of a pair of landing lines dropped from the nose of the ship at 7:21 pm, the Hindenburg suddenly burst into flames and dropped to the ground in just 37 seconds. Of the 36 passengers and 61 crew on board, 13 passengers and 22 crewdied, as well as one member of the ground crew, making a total of 36 lives lost in the disaster.
The exact location of the initial fire, its source of ignition, and the initial source of fuel remain subjects of debate. The cause of the accident has never been determined conclusively, although many hypotheses have been proposed. Escaping hydrogen gas will burn after mixing with air and will explode when mixed with air in the right proportions. The covering also contained material (such as cellulose nitrate and aluminium flakes) which Addison Bain and other experts claim are highly flammable when combined in the right proportions. This theory is highly controversial and has been rejected by other researchers because the outer skin burns too slowly to account for the rapid flame propagation and hydrogen fires had previously destroyed many other airships. The duralumin framework of Hindenburg was salvaged and shipped back to Germany. There the scrap was recycled and used in the construction of military aircraft for the Luftwaffe, as were the frames of Graf Zeppelin and Graf Zeppelin II when they were scrapped in 1940.
(The article image was colorized by redditor Dana Keller)