An explosive mixture controller must ensure that when the mixture is being made a notice showing the words set out in table 68.1, in conspicuous red letters on a white background, is prominently displayed—
(a) if the mixture is made in the open air—at the mixing point; or
(b) if the mixture is made in or on a building or structure—outside every entrance to the building or structure.
Table 68.1 Text of notice
DANGER
EXPLOSIVES
NO SMOKING OR FLAME