16.4.1 During handling and
carriage of cargoes producing flammable and/or toxic vapours or when
ballasting after the discharge of such cargo, or when loading or unloading
cargo, cargo tank lids shall always be kept closed. With any hazardous
cargo, cargo tank lids, ullage and sighting ports and tank washing
access covers shall be open only when necessary.
16.4.2 Personnel shall not
enter cargo tanks, void spaces around such tanks, cargo-handling spaces
or other enclosed spaces unless:
-
.1 the compartment is free
of toxic vapours and not deficient in oxygen; or
-
.2 personnel wear breathing
apparatus and other necessary protective equipment, and the entire
operation is under the close supervision of a responsible officer.
16.4.3 Personnel shall not
enter such spaces when the only hazard is of a purely flammable nature,
except under the close supervision of a responsible officer.