|Urushiol Oil is Potent
Only 1 nanogram (billionth of a gram) needed to cause rash
Average is 100 nanograms for most people
1/4 ounce of urushiol is all that is needed to cause a rash in every person on earth
500 people could itch from the amount covering the head of a pin
Specimens of urushiol several centuries old have found to cause dermatitis in sensitive people.
1 to 5 years is normal for urushiol oil to stay active on any surface including dead plants
Derived from urushi, Japanese name for lacquer