I used to use Shelltox mini strips for years and never had one problem. I used to rip the packet open and throw the strips into enclosures overnight. Pythons would sit on the strips, tongue flick the strips etc...but never a dead snake and never once any sign of the strips effecting any snakes. I would like to point out that i didnt do this because i'm a careless, irresponsible keeper, it was done because back then i didnt know any better (it was years ago when i was young) But it shows that they can be used with caution. Anyway i'm now loyal to TOD and havent used a pest strip in years.
As far as i know these strips are now band because they contain dichlorvos.