BT BQ 9b(32) :התם ציבתא דחרש קא גרים הכא לאו צבתא דחרש קא גרים‏ : in that case the deaf mute's use of the tongs is the cause (of the damage directly); in this case the deaf mute's tongs are not causing it
See the entire entry for ṣbt#2 n.m. tongs