[NineOhOne]

WD-40's formula is a trade secret. The product is not patented in order to avoid completely disclosing its ingredients. WD-40's main ingredients, according to U.S. Material Safety Data Sheet information, are:

• 50%: S t o d d a r d solvent (i.e., mineral spirits -- primarily hexane, somewhat similar to kerosene)
• 25%: Liquefied petroleum gas (presumably as a propellant; carbon dioxide is now used instead to reduce WD-40's considerable flammability)
• 15+%: Mineral oil (light lubricating oil)
• 10-%: Inert ingredients

The German version of the mandatory EU safety sheet lists the following safety-relevant ingredients:

• 60-80%: Heavy Naphtha (petroleum product), hydrogen treated
• 1-5%: Carbon dioxide

It further lists flammability and effects to the human skin when repeatedly exposed to WD-40 as risks when using WD-40. Nitrile rubber gloves and safety glasses should be used. Water is unsuitable for extinguishing burning WD-40.


The WD-40 web site states that it is a petroleum based product.