I had a New Goodman hvac split system installed. That I bought online. Supply plenum on top of air handler was coated with DP 1030 mastic on outside and… THE WHOLE INSIDE.  Says on container: Water Based, Non-Toxic, No Voc’s, but I also heard that mastic should not of been put in the air stream. I have extreme chemical sensitivity’s so have to be very careful about these things. And I’m concerned whether should leave it or have it replaced by another a/c contractor. This SO CALLED CONTRACTOR, was from Craig’s list. Took money and run kind of guy. I am not using it at this point until I find out if it is safe. The system seems to be running fine quiet & cooling great.  Just concerned about the mastic issue.  Thank you, Dale