(1) No person carrying out any operation referred to in regulation 39(1)(a) or (b) or (5)(a) or (b) shall-
(a) smoke; or
(b) carry any naked flame.
(2) No person shall place or carry on a gas vehicle-
(a) subject to paragraph (b), any artificial light other than a light which is not liable by virtue of its construction to ignite flammable vapour;
(b) any artificial light which is liable to ignite flammable vapour unless it is permanently fixed to a part of the vehicle which is not likely to come into contact with flammable vapour; or
(c) any explosive substance or article capable of causing a fire or explosion, including matches and cigarette lighters.
(3) No person shall place any goods in the cargo compartment of a cylinder wagon at any time when there is any cylinder in that compartment.