Air Conditioning - Dow Great Stuff - Is it any danger if it gets into my duct?

Hello--

I am installing an air conditioning duct into a room, and I had to run the duct from the attic, along the edge of a room (will be soffitted later), and thru the wall into the room where I was putting the hit. Since I made a sheet metal box to project the air through the wall, I wanted to seal up the edges of the sheet metal and give the box some insulation as it goes through the wall. I took a can of Dow GreatStuff expanding polyurethane foam and sprayed the seams and all around the duct. It hardened nicely, but then I noticed that some of it creeped into the interior of the duct through the seam. Not much, but a little bit.

The question is--is this any danger to people breathing the air from the duct to have some foam in the air passage? Seems to me that all those vapor warnings on the can are for when you are spraying it, and once it hardens, should be no problem for it to be inside an air duct a bit. The website even recommends sealing the edges of air ducts with it. Just want to see if I should be doing anything to seal over the foam to keep the air from flowing over it, but anything I seal it with would probably be just as bad. Any thoughts, or am I just being paranoid?

Thanks!

The only danger would be if there were a fire. Most foams are highly toxic when burned. Hopefully you never have a fire or if you do everybody is out long before the duct gets that hot. Basiclly, don't worry about it.

I like you have some health questions about the stuff. I used it in my drywall for insulkation. Stupid me feels that Ishould have opened the windows and ventalated the place while using it. Didn't do that because of winter. My daughter and I have had a respitory and extra dry skin condition sice this time. Did you ventalate well? Did you use alot of the stuff? Several botlles. Hopwe you are still on the web site. Anybody else have health issues after using Great Stuff?

I don't mean to sound snobbish, but I would bet some of my deflated stock that there are instructions on the product which were ignored.

Chief, I agree with Grady - don't worry.

Jeff, sounds more like a low humidity issue than a Great Stuff reaction.

Goldstar, they don't just print the usage instructions to protect from lawsuits. Read and head! Keep your stock.