Schoelt

Schoelt was a pre-War company that sold propane fuel, and was established in the year 1895.

Appearances
Schoelt is mentioned only in Fallout 4. There are billboards and posters of the company logo scattered all across the Commonwealth.

Behind the scenes
In the real world, propane was not sold until 1911, or even known before 1910. Since the Fallout universe was not supposed to be diverging this early, possibly the Schoelt company originally sold other fuels.