Kerosene is blue because a blue dye which is called Solvent Blue 35, is added to it to help distinguish it from other fuels like petrol and to make it easier to identify. This is a safety precaution to avoid unintentionally using the incorrect fuel. The blue colour also aids in identifying whether the kerosene has been tainted or contains water, both of which can impair its efficiency.

Oil companies use rail to transport over 98% of kerosene from refineries to depots in ‘neat’ condition, or without colour. Pipelines are used to move the residual fuel. To indicate the plain kerosene as a discounted product, which costs less than half as much on the free market, a blue dye is applied at depots.

In Australia in the 1950s, kerosene had no colour. People, typically youngsters, frequently died after drinking it from bottles thinking it was lemonade, water, or another colourless beverage. Blue was chosen since it least resembled bottled drinks because they were brown, red, green, yellow, etc. Later, a bottle with a unique form was developed. Deaths from kerosene use are now essentially unheard of. Kerosene may have a distinct colour in other nations (red/blue) due to different tax laws and government subsidies. Kerosene is not subsidised in Australia; you must pay the entire amount, including taxes.