Diesel fuel with red dye added. The color does not change how it burns. It marks fuel that the highway tax was not paid on.
Dyed diesel is the same fuel as regular road diesel, dyed red so anyone can see the road tax was skipped. Because that tax was not paid, it is legal only for uses that stay off public roads, such as farm tractors, generators, heating, and construction equipment.
The dye lets an inspector check in seconds. Red fuel in the tank of a highway truck means the road tax was dodged, and the penalties are heavy.
A jobber tracks dyed and clear diesel separately, because they carry different taxes even though they come from the same supply.
In useThe jobber delivers red dyed diesel to a farm’s tank for the tractors, and clear, taxed diesel to the trucking fleet next door.
Where the word comes from
The red dye comes from tax rules that mark untaxed off-road fuel so it can be spotted at a glance. The fuel takes its name from that dye.
See also Kerosene, Motor fuel excise tax