mike I had the exact same thing at a large commercial customer of mine. Probably 200 sq ft of carpet the "off gassing" from the glue was creating a problem and people were complaining of headaches and sickness. They called me to clean I went in and when we opened the door it was real strong, after the door was open for a while it wasn't as bad. real obviouse that the air was not circulating enough to ventalate the room. I told them it didn't need cleaning they told me to go a head and clean anyway, which I did. I then instructed them to get a fan in the room to constantly recircualte the air. The fan fixed the problem, however they are convinced that it was the cleaning and now call me to clean any new carpet they install, which in a facility this size is quite often. Gotta love cleaning clean carpet
So I would have them check the filters in their furnace, run the furnace fan in the on position and clean if they insiste or ifv you feel comfortable clean it anyway as an added precaution and to show you've done all you can.