I have yew tree paranoia, please help?

nb. hypochondria in progress

When something hit the leaves, a white dust came off them. I saw some small yellow things coming off the branches, so I was thinking maybe this dust came out of them, like a way of seed dispersal. But the reason I am scared, is because yew trees are poisonous, and I am worried what will happen if I inhaled it or any went in my mouth. =|

Does anyone know?
Sorry if I’m being stupid, but anything that can make me ill makes me panic… =S