In its pure form, the amount of Urushiol Oil you could fit on the head of a pin could make 500 people very miserable. Because Urushiol is oil, and not a water based fluid, it does not evaporate; therefore it can linger for at least a year. It will cover what ever it comes in contact with such as clothing, tools and even pet hair.
Because it is oil, Urushiol will vaporize when it is burned. The vapor is then carried in the smoke and covers everything it comes in contact with; which means it can continue to contaminate for a year or longer! Urushiol is present on the leaves, stems, and roots of the plant, and is still active even on dead plants that have dried up.