“…Another rosin-sensitive worker became reactive to pine trees and even unheated rosins or turpentine (144). In addition, bronchoprovocation tests have been positive in previously sensitized workers after exposure to concentrations as low as the current limit of chemical detection (i.e., 7 pg/m 3 toluene diisocyanate) (145)(146)(147)(148). Thus, once hypersensitivity has been initiated, the dose necessary to elicit subsequent response can be extremely low.…”