hey Linds;
If you have the soft blackish stuff, it's fibreglass. Crickets will eat through it if they can get at it for any length of time, other than that, the only concern is .. you guessed it, it will offgas for a short period if exposed to a high heat source (like using it for a light screen). But it's screen, so it is well ventilated and shouldn't cause too much problem. (If I keep coming up with this offgas stuff I'm gonna get a nickname that I probably won't like!)
By the same token, if you use the metal screen (grey in colour and rougher) it can hurt the snakes nose if he can rub against it.
Keith