Not off-hand- & when I first came across that, I shared it here on this site. It's been quite a while- anyway, the lead was mostly manufacturing dust from the pliable wires used inside the plastic leaves- & the fact that little kids like to touch things & then stick their fingers in their mouths (or eat with their fingers, hands unwashed), so thoroughly washing the fake plants would help that.
My more immediate concern would be when leaves come off & the sharp wires get exposed, & snakes can can injured on those. That's what I suspect occurred with the OP's snake, from the description given. Without even seeing the snake in question, this was just my "brain-storming" & trying to solve the mystery.