19. Coloured fuel oil may be acquired or used for all purposes other than supplying a propulsion engine, except the propulsion engine(a) of a pumper truck while used to fight a forest fire;
(b) of a railroad locomotive;
(c) of a vessel described as a commercial vessel by regulation, provided that it be put directly into the tank installed as standard equipment for supplying the engine;
(d) of farm machinery, except a pleasure vehicle or truck, but only while the machinery is used for farming work, provided that the principal occupation of the consumer of the coloured fuel oil is farming in respect of an immovable the consumer owns or leases;
(e) of a fishing boat, but only while the boat is used for fishing, provided that the principal occupation of the consumer of the coloured fuel oil is fishing or the processing and marketing of fish; or
(f) in the cases, for the purposes and on the conditions determined by regulation.