Another avenue that has intrigued investigators is the Hindenburg's skin. This subject is of particular interest to a former NASA employee named Addison Bain who believes the hydrogen gas aboard the airship is not to blame for the cause of the fire or its rapid spread. He instead believes the outer skin of the airship first ignited and the hydrogen would never have burned if the skin hadn't already done so. This flammable fabric theory is based on the Hindenburg's skin coating that consisted of iron oxide and aluminum-impregnated cellulose acetate butyrate dope. The doping material is known to be a flammable substance, and iron oxide also energetically reacts with aluminum powder. Since iron oxide is mixed with aluminum to create the explosive substance thermite and aluminum powder is often used to boost the performance of solid rocket motors, proponents of the flammable fabric theory frequently exaggerate by stating the Hindenburg was "coated in rocket fuel."

Evidence supporting the fabric theory is the Hindenburg remaining in level flight for several seconds after the fire began. If one of the hydrogen cells had ruptured due to a gas fire, supporters of the theory argue the ship would have started to tilt towards the ground almost immediately. If the fire were constrained to the skin, however, the cells would have remained intact much longer and kept Hindenburg airborne. Proponents also suggest Zeppelin engineers realized the danger of the skin coating after the disaster and secretly changed its composition on the Graf Zeppelin II. The new coating was said to include a fireproofing agent plus the aluminum was replaced with the less combustible metal bronze.

Nevertheless, more recent research conducted at the University of Colorado has contradicted this theory and found the airship's skin could not have been responsible for the fire's rapid spread. This theoretical and experimental research suggests that even if Hindenburg had been coated in actual solid rocket fuel, it would have taken at least 12 hours to burn in the absence of hydrogen. Experiments with recreations of the ship's skin have also found it would have taken some 40 hours for the Hindenburg to be consumed if the fabric had caused the fire. These finding led the researchers to conclude that although the Hindenburg's skin was combustible, it was not flammable.

Given the inability of investigators to conclusively determine why the Hindenburg crashed, it is not surprising so many theories to explain its destruction have emerged. Even so, the static spark theory is still considered the most likely since it is the best corroborated by the wreckage, video and photo evidence, and eyewitness reports. This evidence and academic research also supports the belief that the ship's hydrogen gas was ignited by static discharge and not the skin. The hydrogen burned explosively and rapidly spread the flames forward throughout the ship, and the skin only burned as a result of this intense fire.