Welding tools can runtime if they run out of fuel when they aren't being held

Created by: gbasood

tools.dm line 444

			to_chat(usr, "<span class='notice'>\The [src] shuts off!</span>")

First of all: >usr Second of all, it doesn't check if usr exists, and because they auto shut off when they run out of fuel, they're runtimes on timers Simplest fix is to just check for usr before to_chatting them, even if it's not the most robust