The 200kg sealed vessel containing hazardous chemicals, which washed up near Kleinjongensfontein beach on the Garden Route, was removed on Saturday by a hazardous materials team.
Further information on the container's origin is not immediately available, but the National Sea Rescue Institute (NSRI) had earlier urged the public not to touch it.
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NSRI spokesperson Craig Lambinon said there might be three more containers either washed up or adrift at sea because such containers are usually palleted in fours.
The public and boaters are advised not to approach the containers, should they encounter them.
Instead, they must immediately notify the Garden Route disaster risk management unit on 044 805 5071 or the National Ambulance Services line on 10177.
Lambinon said: