Ask upfront for a clear timeline and scope of work so you can plan accordingly.And if you’re planning to be on-site at all, I highly recommend investing in a high-quality respirator.

Proper ventilation and respirators are required.

I required that all the people doing the work use respirators.

If there is black mold in the attic, you need to careful in touching it - wear a respirator to avoid health issues.  

.☐ Wear protection: Use gloves, N95 respirator, goggles, and protective clothing.4.

If the home is stripped to the studs, and I personally do the work, wearing a P99 full face respirator along with full body disposable suit... the place is aired out, I give the chemicals time/heat to volatilize...

I had to wear a respirator to stand it.

We had to wear suits, respirators, safety glasses, and gloves.

@Adam DrummondAdam, your profile tells me you've been in the business for a bit, but still, word to the wise -- respirator with organic vapor cartridges is a must when working with oil-based poly.

Those paint strippers will eat right through organic vapor catridges in a respirator, and they really don't work all that well anyway without multiple, repeated applications.After the heat gun, you might want to try the Citristrip product on trouble spots.