39. The malfunction of, or development of a defect in, breathing apparatus or a smoke helmet or other apparatus serving the same purpose or a self-rescuer where—
(a)the malfunction or defect causes, or is likely to cause, a significant risk of personal injury to the user; or
(b)immediately after use and as a result of its use any person receives first-aid or medical treatment because of that person's unfitness or suspected unfitness.