Like its cousin Florida Poisonwood (Metopium toxiferum), it produces urushiol in its bark, which can cause contact dermititis on one's skin when touched; therefore live trees and fresh cut logs should be handled carefully.
Pacific poison oak skin contact first causes itching; then evolves into dermatitus with inflammation, colorless bumps, severe itching, and blistering.
Ginkgo biloba and cashew, plants containing chemicals closely related to urushiol.