And I spent a lot less time on my belly in a crawl space with a respirator on. :-)

Respirators are really intended to be back-up protection when "engineering controls" such as adequate wetting fail.

AND WEAR A MASK OR RESPIRATOR!

.******* I am not a doctor or lawyer or advising anyone to go start eating popcorn ceilings or huffing asbestos******What casey states is correct, however if you are going to DIY spend money on the best respirator mask you can find at home depot, and if you are going to remove the carpets, and you want to scrape the popcorn ceilings, use a hose to soak the ceiling to make it come down easy and  to lower the dust particles in the air.

@Linda ThomasIf you have a respirator wear one to the house if you’re doing the repairs.

Whomever does it needs to wear protective gear and respirators.

The tenant called me and said she needed more time because her husband was in the hospital on a respirator for 38 days.

We bought one that had 10 cats in it and it was so foul we had to use respirators to be able to clean it out.  

You will want very good ventilation or a respirator when you apply either ... though the alcohol in the Zinsser will dry and dissipate more quickly.

It was so bad that the 2nd contractor to come in told me and my RE agent that we should leave the house for a bit as we had been inside the house for nearly an hour with no respirators or anything on...