Thanks Talpa for your reply, I really appreciate it.
Yes the sheet that comes with it rather makes it sound very scary indeed. I am a bit of a worrier when it comes to chemicals spreading round the house, for example, the porch was treated, and a package was left in it by a courier after it had dried, and my partner lifted up the package, opened it and then open his beer! I was immediately worried he'd poison himself somehow, but your explanation helps, as I guess even if there was a tiny amount transferred to the package it would be unlikely to be in sufficient quantity to do any damage