I recently had an asbestos abatement contractor in my home to remove vinyl tile and mastic from my basement. They used the solvent MastAway MA-33 (MSDS) to remove the mastic, and it is leaving very strong fumes in my house. It was bad enough that I decided to call in an air quality testing company. They took two sets of readings - one with a handheld total VOC meter, and another that got sent to a lab.

The asbestos work was done on Dec 5. The handheld VOC meter read 8000ppb in the basement and 3000ppb in our first floor bedroom on Dec 8, 3 days later. The air quality company was blown away and warned that the house was very dangerous. We started actively ventilating the house that night (even though it's below 30F outside), and 24 hours later the levels had dropped to 2600ppb in the basement and 700ppb in our bedroom. Still bad, according to the air quality tester, but better.

I contacted toxicologists at my local poison control center and local public health center, and both thought that given the MSDS and meter numbers from the air quality company, that we were fine. They recommended using 10% of the OSHA TWA in the MSDS as a safe residential exposure limit. That would be 10ppm for the main ingredient, and we were at 8ppm at the highest (in the basement, with no ventilation).

I've just received the report back from the lab on the sample the air quality company took, and it is also not good. The sample was taken the same time as the first set of handheld readings - when the house was closed up on Dec 8, three days after the asbestos work. The lab's threshold level for "severe" in a house is 3000ng/L, and our house has 26000ng/L (210ng/L of 2-butoxyethanol and 23000ng/L of solvents, so mostly from the chemical the the asbestos company used).

I'v sent this report to the toxicologists, but I'm wondering how to interpret this. I see some websites cite that levels above 500ng/L are dangerous, and we have 26,000! One website described total VOC levels over 25,000 as "toxic range, potential neurological effects."

My wife and I don't seem especially symptomatic. Our eyes are slightly irritated, but our house has been getting really dry with the windows open. Despite this, I'm worried sick for my wife (pregnant) and dog.

So, I guess my question is: how do I weigh these results against standard total VOC cautions? My air quality company is shocked, but they're going off recommendations for total VOCs. Given that we know what makes up the VOCs, and after doing due diligence, the concentrations seem fine, although obviously not ideal. I have no idea how long these fumes will take to dissipate. I suspect they soaked too much into our concrete slab. I fear that if I stop ventilation, the levels will just creep back up.

Thank you very much for any help!