WD-40 is the trademark name of a widely-used penetrating oil (and cleaner, dielectric and anti-corrosion) spray solution commonly sold in hardware stores and other such retail outlets. Developed in 1953 by Norm Larsen, then working for the San Diego Rocket Company, it was originally designed to repel water and prevent corrosion, and later was found to have numerous household uses.
WD-40 stands for Water Displacement, 40th formula. Larsen was attempting to concoct a formula to prevent corrosion, by displacing the standing water that promotes it. In the process, he arrived at a successful formula on his 40th attempt. WD-40 is primarily composed of various hydrocarbons.
WD-40's main ingredients, according to U.S. Material Safety Data Sheet information, are:
The German version of the mandatory EU safety sheet lists the following safety relevant ingredients:
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.
There is a popular urban legend that the main ingredient in WD-40 is fish oil. Although it is unknown whether the formula contains fish oil, material safety data sheets for the product show that the main ingredient is Stoddard solvent, not fish oil.
In 1969, the San Diego Rocket Company renamed itself WD-40 after what was then its only product, but WD-40 was still sold as "Rocket WD-40" for many years, with the history of its use in preserving Atlas rockets printed on each can. The company went public in 1973. Its NASDAQ stock symbol is (). In recent years the WD-40 company has acquired several household-products companies, adding such brand names as 3-In-One Oil, Lava, Spot Shot, X/14, Carpet Fresh, and 2000 Flushes to its roster. The company still has its corporate offices in San Diego, California. It now markets its products in more than 160 countries around the world. In 2003, it recorded sales of $238.1 million.