SANTA MARGARITA (CBS SF) — Nearly 200 firefighters battling a blaze on California’s Central Coast had to be treated for poison oak.

Firefighters battling the Cuesta Fire near Santa Margarita suffered allergic reactions due to the plant.

The fire is in steep, rugged terrain in San Luis Obispo County, where poison oak thrives, and Cal Fire says there’s no way for firefighters to avoid it.

That wildfire is now 85-percent contained.