It depends what kind of cedar you used. Red cedar causes sensitivity in more people than white cedar.

Cedar grows in wet ground well. One thing that it has to adapt to this environment and fight the bacteria that would rot it out while still young is that it has it's own aromatic oils and some toxic compounds. cedars that grow in jungle areas of the world have more of these than those that grow in colder, drier places. These are the toxins that keep cedar fence posts from rotting and that make a closet smell nice while repelling moths.

If you didn't have a reaction to the dust while actually doing the sanding, you have little to worry about. Most woodworkers who create cedar dust learn eventually that it is good to wear a dust mask.

I have quit using Port Orford cedaar very much because it has irritated the sinuses of my crew members and it landed me in the hospital with a lung irritation that gave me symptoms like a heart attack, great pain with every atempt to breathe in.

Ouch! I know that feeling, had it with drywall dust, gave me flu like symptoms and made me sick for weeks. Another wood to watch out for that is extremly hazardous is ebony, its dust has the same properties as asbestos, and proper precautions must be made when working with it.

It's interesting. In some tabloid type magazine, I came across an artile saying that twenty substances were just added to the official list of things that are know to be able to cause cancer. it said, "some kinds of wood dust like cabinet makers use" but failed to let us in on the big secret.