The ultra-large container ship heading to Le Havre from Asia encountered bad weather in the Indian Ocean near the city of Durban on July 9, the South African Maritime Safety Authority (Samsa) said.

Aerial surveys of the area were being carried out to trace the containers and other vessels in the area have been asked to look out for them, Samsa spokesman Tebogo Ramatjie told AFP.

“We’ve received information from passing ships. Some of them spotted containers in the area but our aerial survey have not found any containers yet,” he said.

The cargo was lost when a container stack collapsed on the Benjamin Franklin, a Maltese-flagged ship owned by French logistics firm CMA CGM.

Thirty other containers were damaged.

“All containers lost at sea contained harmless goods and do not contain any dangerous cargo,” CMA CGM said in a statement last week.

Severe storm conditions near the Cape of Good Hope last week severely disrupted shipping.

The route has seen an increase in traffic in recent months as ships seek to avoid the Red Sea route because of the threat of attack from Yemen’s Houthi rebels.

Heavy seas led 18 Filipino crew from a Panama-registered cargo vessel to abandon ship off South Africa’s west coast on July 9.

The MV Ultra Galaxy was beached northwest of Cape Town today as operations were underway to seal its fuel tanks to prevent an oil spill, Samsa said.

The vessel was headed to Dar es Salaam and carrying fertiliser – a significant portion of which was swept away.