Many years ago I did some research on poison ivy and oak for the FDA. I
had to isolate and purify nearly a kg of urushiol, a process that
eventually required about 500 lbs of both plants. The collections were
made locally in northern Mississippi and absolutely required fresh plant
material. Once the leaves have lost pigments and dried, then the
urushiol levels rapidly decline since it has a chemical structure that
makes it rather susceptible to degradation by sunlight and O2. Burning
such dried material would be much safer than attempting to burn fresh
material with gas or other fuel, a process that can indeed lead to the
toxin being present in smoke particles. However, it is unlikely to
adversely affect most people, even those allergic to the toxin (as most
people are). Unfortunately, individuals who are extremely sensitive to
urushiol, and who are thus most likely to display a generalized systemic
reaction to traces of urushiol, would be the ones at significant risk.
An NMR technician working with my urushiol required emergency
hospitalization after accidently exposing himself to a very small amount
of urushiol. Such a person would be at great risk if exposed to smoke
from the burning of such materials.
Michael Corbett, Ph.D.