[1_Rain_Drop]

"Most saw dust should be avoided. Hardwood, especially oak, has a saw dust that can kill."

Interesting.

I did buy the DF from a lumberyard and it sat in the house for close to two years before installation

After the DF floor was installed, the dude sanded it and then packed sawdust into the minor imperfections. (I think he skipped the part where sawdust is to be mixed with wood glue, then applied). After he left, I vacuumed that sawdust considering that when poly will be applied that sawdust will mix with the poly and create a visual nightmare.

[kiryandil]

Mix the fine sawdust from the sanding of the doug fir with lacquer, to the consistency of runny baby poop.

Use a putty knife to pack the cracks in the floor, then do the hand sand after the lacquer/sawdust mixture dries.

Vacuum once again.

Lacquer is pretty nasty, so wear a respirator.

[kiryandil]

After he left, I vacuumed that sawdust considering that when poly will be applied that sawdust will mix with the poly and create a visual nightmare.

I forgot - just so. It would be vile.

[KC Burke]

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.