Holds containing these substances shall be ventilated whith the ventilators operating at full power, where after measurement it has been established that the holds are not free from toxic gases and vapours given off by the cargo. The measurement shall be carried out immediately after loading. A control measurement shall be repeated after one hour. The results of the measurement shall be recorded in writing.

Alternatively, on vessels only containing these substances in containers in open holds, the holds containing such containers may be ventilated with the ventilation operating at full power only when it is suspected that the holds are not free of toxic gases and vapours given off by the cargo. Prior to unloading, the unloader shall be informed about this suspicion.