Further, he determined that the substance was a type of alkyl catechol, and due to its structure it was able to penetrate the skin and survive on surfaces for months to years. Urushiol's ability to polymerise into a hard glossy coating is the chemical basis for traditional lacquerware in many Asian countries. After urushiol comes in contact with oxygen, under certain conditions it becomes a black lacquer and has been named urushi lacquer. Characteristics Urushiol in its pure form is a pale-yellow liquid with a specific gravity of 0.968 and a boiling point of . It is soluble in diethyl ether, acetone, ethanol, carbon tetrachloride, and benzene. Urushiol is a mixture of several closely related organic compounds. Each consists of a catechol substituted in the 3 position with a hydrocarbon chain that has 15 or 17 carbon atoms. The hydrocarbon group may be saturated or unsaturated. The exact composition of the mixture varies, depending on the plant source. Whereas western poison oak urushiol contains chiefly catechols with C17 side-chains, poison ivy and poison sumac contain mostly catechols with C15 sidechains. The likelihood and severity of allergic reaction to urushiol is dependent on the degree of unsaturation of the hydrocarbon chain. Less than half of the general population experience a reaction with the saturated urushiol alone, but over 90% do so with urushiol that contains at least two degrees of unsaturation (double bonds). Longer side chains tend to produce a stronger reaction. Urushiol is an oleoresin contained within the sap of poison ivy and related plants, and after injury to the plant, or late in the fall, the sap leaks to the surface of the plant, where under certain temperature and humidity conditions the urushiol becomes a blackish lacquer after being in contact with oxygen. Urushi lacquer is very stable. It is able to withstand disturbances from alkali, acid, and alcohol, while also being able to resist temperatures of over 300 °C. However, the lacquer can be degraded by UV rays from the sun and other sources. Within the United States, urushiol-containing plants are widely distributed. Poison ivy can be found in all states except California, Alaska, and Hawaii. Poison Oak can be found on the west coast or in some states in the southeast, while poison sumac can be found only in the eastern half of the country. These plants all have distinguishing features that will help in identification. Poison