Maybe I just worry too much, but when it comes to what things are harmless or deadly to the critters, I always assume the worst. I don't know if it was mentioned, but ventilation and a good exhaust fan would be important too. The fumes usually smell terrible, and I would not want to take a chance, given some of the warnings I've read about cyanide fumes, etc. Better safe than sorry. Even the harmless stuff stinks something awful.