Great Stuff (3M) FireBlock is a total scam. I've tried new and cured (3 years) and the stuff burns like it's made of gasoline. I believe many of the "Fire Block" products are like this. Fire Block prevents drafts, restricting the air being supplied to a flame. That's their justification at least.

https://www.finehomebuilding.com/for...lock-watch-out

https://statlerprojects.wordpress.com/598-2/

https://ecorenovator.org/forum/showthread.php?t=3322