Well....I do recall a narrowboat explosion from expanding foam...and I also found this on the 'net'...but it may be a different type ?..
I'm interested as I have been wary of using it myself...and it would have been handy.
Smoker sparks house explosion
TWO terrace houses were nearly destroyed when a cigarette triggered a large explosion. Five fire engines were called to Portland Road, Croydon, at about 7pm yesterday to tackle the resultant blaze. One person was slightly injured.
It is thought that building work was taking place involving expanding foam a?
used as a filler a? and someone lit a cigarette and ignited the vapours. The blaze took 90 minutes to bring under control and the fire brigade fears the buildings could collapse.