Is steel wool dangerous ? It certainly is if you dunk it in liquid oxygen & then turn a gas torch on it !
I'm still puzzled as to how steel wool to rodent-proof houses is such common practice, if it's dangerous. Also I presume the kind of wiring in this picture under the bathtub (i.e. earthing) is NOT a risk with regard to steel wool:
Actually I reckon this stuff (although not as flexible) is safer? Stainless steel rather than steel: http://amzn.eu/3FkQCSU