The formaldehyde was not the real issue with that type of foam as an
insulation product. All sorts of things give off tons of formaldehyde,
carpet, your new car, some paints, and furniture. The problem with the foam
as insulation is that it shrank over time and thus allowed thermal bypasses
to form and total loss of R value. The Urethane form you get (great stuff)
is non shrinking and a different catalyst. For small air sealing it is
fine, but do not inject into cavities that can be damaged by the expanding
foam pressure. Use a low expansion (window and door) foam for filling
window cavities and other sensitive spaces.

TAB Dude

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