Container fumigation is the treatment of a commodity or the container itself to eliminate the risk of pests or disease from entering or leaving the country or state.
Containers can be fumigated at different times in the transport chain. If done offshore before shipment, the container will usually be aerated or ventilated before loading on a ship. Under international maritime rules containers under fumigation are only permitted on a ship at the discretion of the master, who will usually require them to be aerated or ventilated. Even if these containers are aerated before shipping, some residue of fumigant is likely to remain because of the slow release of gas absorbed into the cargo. Documentation about fumigation of a container such as treatment certificates, customs declaration or warning labels may not be a reliable indication that fumigation has been carried out. Therefore anybody required to open a container must do so with great care and take appropriate precautions to prevent exposure to possible toxic gases.