|This oil is called urushiol. Urushiol is found in all parts of the poison oak plant, including the leaves, stems, roots and berries. This oil is easily accessed; it is present on the surface of the entire plant. All you have to do is touch a part of a poison oak shrub and you will come in contact with urushiol.
Doesn't matter how dense or thin the oil content is, any exposure to the oil will cause an outnreak.