Disposing of Spent Spray-Foam Canisters
I recently tested two-part spray-foam kits for Fine Homebuilding. Surprisingly, finding out how to dispose of the spent tanks and hoses proved to be the most difficult part of my testing because the rules are very different depending on where you live. Makers skirt the issue by saying “disposal must be in accordance with federal, state and local laws.”
My state’s (Connecticut) Department of Environmental Protection couldn’t say whether the material was considered hazardous waste without testing, because the Material Safety Data Sheets proved inconclusive.
‘Liquid leftovers’ are the biggest problem
One forthcoming spray-foam company rep told me (off the record) that liquid leftovers are the biggest potential problem, so she suggested dispensing any remaining liquids into a waste container and letting them dry. Once the liquid chemical is gone, you should invert the tank and bleed off the propellants, which are a mix of nitrogen and the refrigerant R134A.
My own experience:
I took one of the kits to my local transfer station, and after a little head-scratching, they told me to bleed off all the gas to eliminate any explosion hazard, then to toss the empty tanks into the metals recycling pile and the gun and hoses in the trash.
I’d love to hear how anybody who has used these kits ended up disposing of them.