I dont know about the rest of the world but in the US they use Butane in lighters, butane is not propane, they are different gasses.
Butane is CH3CH2CH2CH3
Propane is CH3CH2CH3 or C3H8
Butane: also called n-butane, is the unbranched alkane with four carbon atoms, CH3CH2CH2CH3. Butane is also used as a collective term for n-butane together with its only other isomer, iso-butane (also called i-butane, isobutane, or 2-methylpropane), CH3CH(CH3)2.
Propane: a hydrocarbon fuel gas with the formula C3H8 that is used primarily as a bottled gas for heating and cooking. Being heavier than air, if propane is in a buried pipeline, it will require a separate pump to bring a sample into a gas detector's sensor chamber.
About the Smell of Propane:
By nature, propane is clear and contains no scent at all. For safety purposes propane companies add a substance known as ethyl mercaptan to the propane fuel. Ethyl mercaptan has a strong rotten egg, or skunk-like scent, which allows the consumer to smell it in the case of a leak. If you smell something similar near your appliances and your tank it is ALSO possible that you are low on fuel. Ethyl mercaptan is heavier than propane and sinks to the bottom of the tank so when the tank is low on fuel the ethyl mercaptan odorant will become even more noticeable.
I couldnt find anything about Butane's smell.
LINKS:
About Butane
About Propane
Oh, and Finally, Desel Fuel (at least as far as I know) does not have any additives to make it smell so wonderful, and yes I mean wonderful( I love tractor trailer trucks, lol) Although here in the US they do add a red dye to it to sell it as heating oil.