see
http://www.tedswoodworking.com/toxic-wood.htm
Respirator masks as opposed to cheap dust masks are the best when sanding down a floor. Douglas fir is not one that has a lot of problems.
Wood shops should have a good vac system around tool usage areas and good exhaust and ventilation systems. The dust can be a fire hazard with heaters that get it into their internals.
Likewise the fumes from a lot of wood working chemicals are best avoided or done outside.
Thank you for the link.
I notice no fruit trees are listed such as cherry.