Cured, correctly-installed spray foam is chemically inert and safe - it's used in millions of homes and buildings. 'Toxic' fears almost always concern either the wet, curing stage (a managed, temporary window) or a botched install, not the finished product.
The two stages, kept separate
- Curing: the two-part chemistry reacts and there's a short emission window; the space needs ventilation and the manufacturer's re-occupancy time respected.
- Cured: the reaction is complete, the foam is stable and inert, and it's covered by a thermal barrier in living space.
Why bad installs cause the horror stories
Off-ratio mixing, wrong temperatures or spraying too thick can leave foam that never fully cures and keeps emitting odour. That's an installer failure - preventable by using a CUFCA-certified applicator working to CAN/ULC-S705.
Bottom line
The product isn't the risk; a bad install is. Vet the installer and follow the cure window, and the finished foam is one of the more inert things in your wall. See is it safe and off-gassing.
Thinking about spray foam? Get a free quote from a vetted Alberta installer.