The ammonium nitrate prills were not packaged in the containers in accordance with the requirements of the IMDG Code. The containers were packed in a way which allowed the prills to move within the container in a way that may have contributed to the failure of the containers and/or the lashing system.
Orica and AMSA have worked to gether to ensure that the IMDG Code shipping requirement are met.
Orica has advised the ATSB that the company has taken two main actions relating to packing of ammonium nitrate for sea transport following the incident. Orica has worked with AMSA to agree on a revised packing procedure for ammonium nitrate prills.
The new approved procedure differs from the previous method in three respects: the plastic liner inside the shipping container is now closed with a zip, rather than tape; the wooden bulkhead has been replaced with a steel bulkhead, in order to reduce the presence of combustible material inside the container, but not, as Orica understands, due to concerns about structural integrity in using a wooden bulkhead; and the containers are now packed with 18.5 tonnes of ammonium nitrate, rather than 19.5 tonnes. Orica has also developed a training program with respect to IMDG compliance which has been rolled out to all Orica personnel and contractors involved in packing and loading of shipments of ammonium nitrate. This program was developed in consultation with AMSA, and has been approved by AMSA.
The ATSB is satisfied that the action taken by Orica Australia adequately addresses this safety issue.