Here is a wood site that describes wood and wood dust toxicity:http://www.wood-database.com/wood-articles/wood-allergies-and-toxicity/
Note that Western Red Cedar is one of the more toxic woods.
I've seen at least three of the directly poisonous woods for sale (Tambootie, Sassafras, and Yew). Personally, I experienced a minor reaction to Mesquite dust. It was minor enough that I still work with it, but I make sure that all of my dust controls are running and I cover as much exposed skin as is feasible. I've also noticed that Wenge splinters pretty much always get infected.
My understanding is that you may work with some of the woods listed as irritants for a while without problems, and then one day you go to the shop and bang! you have a reaction. That has happened to my son with two different woods now, after about 15 years of woodworking. Black Locust was one if I remember correctly - it's available locally as urban lumber. While most of the woods on the list are just irritants that only cause problems very occasionally, I have always avoided the woods that have the potential for worse symptoms - Yew and Sassafras, for instance, both of which sorely tempted me until I read the toxicity report.
Why did I spend mucho bucks for the Festool sanding / vacuum combination? Because too much dust was getting away from my DeWalt / Fein combination. I decided that I wanted a combination that was designed to capture the maximum, and so far, so good.