How potent is urushiol?
Urushiol is amazingly potent. Basically, the smallest amount you could measure would be enough to start the rash. An amount the size of the tip of a needle is enough to start and spread the rash. Indications are that urushiol would have to be diluted down to 1 part urushiol to 60,000 parts olive oil before the potency of the urushiol was diminished.