As the people of Tauranga are once again having to deal with an oil spill in their harbour, we can't help but look back at the threat that sunken ships pose to the environment.
The insurers of the MV Rena have spent millions paying for scientists to prepare reports that say it is okay for them to leave a wrecked mess of pollutants 22 kilometers off the coast of the Bay of Plenty.
As I have said before, the wreck has a whole container of toxic plastic resin pellets on board. It is also inevitably covered in toxic paint and full of fireproofing materials and PVC - all contaminants that will get into the food chain.
The insurers have applied for resource consent to leave the wreck down there simply so that they don't have to pay to remove it. They are essentially offering to instead pay a much smaller amount of money to community projects - which smells as much as the rotten bird carcass covered in oil that I found at the base of Mount Maunganui during the cleanup.
It is evident from history that it is possible to remove the wreck, it is just that the owners and insurers don't want to pay.
But what about oil that sits on board sunken ships?
Just outside the Hauraki Gulf, the HMS Niagara lies 400 feet down, in between the Hen and Chicken and the Mokohinau Islands. It was sunk by a German mine in 1940.
Again this shows how money drives danger.
As this article from the Listener describes, a large amount of gold bullion was removed, but there is a high chance that over a thousand tonnes of oil will be released as the tanks rust away undersea. This threatens to infect the Hauraki Gulf with oil.
The Niagara is one of a number of undersea time bombs that have sunk and will, unless dealt with, cause pollution problems.
Across the Pacific there are 3,800 wrecks from World War II that are over 70 years old and will threaten the fragile ecosystems of developing nations such as the Federated States of Micronesia and the Solomon Islands.
Will this be another case of official responses waiting until there is a problem until acting? Or might we finally see some strategy put forward to remove this undersea mess before it causes more grief?