I was a kid and lived there, Nafta, is Diesel. it was named that and still is.
It really is a tradition, as in France it is still called Gazole, go figure
In the 50's, 60's, cars (Italy) were Gasoline, only a few oddball autos from the frozen North used Diesel.
Trucks used Nafta, we used Nafta in winter for the boiler room, low quality as available, a truck would show up
with a huge tank and deliver it for the building, or house.
Trucks were not particularly picky with fuel at the times, noisy and smoky.