Hi Christine, MJ here
It was definitely Poison Hemlock - it was only in one place as of now. We worked in the beds along the sidewalk on Stanton and removed larger weeds from interior beds. We both had long-sleeved shirts & long pants on and waited to remove it until we had all of our tools and other items stored before touching it. Gloves were made with all rubber fingers and woven stretch backs. The dead plant is in the bag closest to the pole on the top of the waste materials. We had no ill effects from removing the plant with a hand mattock.
We didn’t search the entire park for more, but saw no other large examples.
Came home and washed clothes and gloves!
We are still working on the curbside on Stanton.
May try to finish before Saturday if the weather holds.