posted 9 years ago
Poison ivy roots can definitely give you the rash even when they are dormant and have no leaves. I've very sensitive to it, but when I am exposed, I always wash with whatever soap is available and then don't get it. Special soap is not needed.
Once a friend and I sat in the winter in New York state making shapes out of nice long roots and runners that had no leaves. Then I remembered that in the summer that area had been full of poison ivy, so we went home and washed throughly with soap. I didn't get the rash that time at all, but the process of drawing his hands through his jacket sleeves left a residue, and a few days later my friend got such bad rashes on his arms that he had to go to the hospital.
Since it's a natural plant oil, I would think it composts fully and turns into harmless materials, but because I'm so sensitive to urushiol, if I had poison ivy vines to compost I'd put them in a separate brush pile in an out of the way place that I'd never have to come back to.
Since you say there were roots in the compost, you might have live poison ivy growing in your compost pile. I'd recommend waiting till it starts to become recognisable in spring, and then ripping out as much as you can, disposing of it where it won't get touched by anyone, and then washing your clothes and hands and body, paying special attention to be paranoid about anything that might have touched anything, like tools, doorknobs, shower curtains, and taps. Just soap and rinse anything that might be contaminated.
Works at a residential alternative high school in the Himalayas SECMOL.org . "Back home" is Cape Cod, E Coast USA.