After the end of the period that applies under regulation 237, the shotfirer must—
(a) thoroughly examine the blasting site and do any work that is necessary to work out the location of any misfire and its cause; and
(b) carefully search for, collect, and safely dispose of any unexploded explosive or debris likely to contain explosive that is on the surface; and
(c) warn all incoming work crews of the possible presence of explosives in any broken ground or rock.