Looks to me like Poison Hemlock. The purple spots on the stem are an identifying characteristic. Nasty stuff. Dig it up(wear gloves), put it in garbage bags, don't compost it, don't burn it as the smoke is toxic. Wash your hands well after touching it(wash your gloves or throw them out after digging up the plant). Your local waste transfer station may let you drop it there for free provided it's bagged alone with no other trash. Don't ever let it go to seed.

Here is a link that might be useful: Poison Hemlock

...for your area:

Here is a link that might be useful: Washington State Noxious Weed Board

Thank you SO much! Will latex gloves be enough? Maybe two layers?

When I worked for a weed board, they provided those gloves that were dipped in latex. They were not waterproof, but provided enough protection, so regular latex gloves should be fine. Just go slow, be careful and launder your clothing(and clean your tools)afterwards.