Pennsylvania Combustible and Flammable Liquids Act (on portable camp stove colour codes)

The law
To prevent confusion between kerosene and the much more flammable and volatile gasoline, some jurisdictions regulate markings or colorings for containers used to store or dispense kerosene. For example, in the United States, Pennsylvania requires that portable containers used at retail service stations for kerosene be colored blue, as opposed to red (for gasoline) or yellow (for diesel fuel).

Also see

 * 1) Significant government and international legislation