Fuel taxes used to be called "Road taxes", as they are used to build/maintain our roads.
As such, the taxes were exempted on any fuels you purchased for non-highway uses.
Thinktractor, chainsaw, weed whacker, log splitter, and, and, and ...
Many states are getting greedy, and using them for other purposes as well.
However, almost every state will give refunds for qualified non-highway fuel use.
The federal government also refunds money for non-highway use.