A long list of risks posed by the wreck of the torpedoed RFA Darkdale sets out grim prospects for St Helena if action is not taken.
Two are rated “intolerable” and highly likely to arise. They are:
- “Catastrophic structural failure of the wreck leading to complete discharge of oil to the environment.” This is rated as probable, with critical impact.
- “Structural failure of a single tank with discharge of contents to the environment.” This could be a frequent event, with major impact.
The Ministry of Defence survey report says: “Structural failure is inevitable – time scale is judged to be within the next 25 years.”
But it says not all tanks are in the same condition and it is more likely they will fail one at a time.
This could actually cause more harm to the environment, because repeated leaks would make it harder for habitats to recover.
The report says there are no simple measures to prevent major leaks.
Visiting vessels, including the RMS St Helena, pose another, undesirable risk, it adds, especially with more cruise ships expected once tourism facilities improve with the opening of the island’s airport.
“Contact of anchor chains with the wreck are highly likely to lead to tank rupture. The increasing number of visiting ships raises the risk.”
Damage to the wreck from severe weather conditions is also rated as probable and intolerable – and increasingly more likely as the structure weakens with age.
“The exposed location of the wreck means that it cannot be protected in any way from the weather,” says the report.
A fourth intolerable risk would bring “disastrous” consequences for the whole island: that supplies of fuel could be cut off if oil in Rupert’s Bay were to prevent a tanker delivery.
But that danger is considered very remote, but the report says: “Given the island’s remote location and dependence on fuel delivered by ship, it would be a very serious impact.
“The building of the airport will increase the demand for fuel on the island, making refuelling more frequent.”
Other threats would bring serious consequences, but are thought unlikely to materialise, or the consequences are not considered severe.
They include the dangers of recreational divers accidentally releasing oil, and harm to the island’s tourism and fishing industries.
The report says the effects of local people eating contaminated fish could be critical – but not likely to happen.
“Samples do indicate fish on the wreck site may be contaminated,” it says, but adds: “Only small quantities of fish are taken from the wreck by a limited number of people.”
And the risk of people in Jamestown being harmed by explosions from the wreck is so low, it is rated as “incredible”.
The report refers to fears that unexploded shells could blow up, especially if disturbed by divers.
But it says: “The vessel is a considerable distance from the town and explosives are all at least 30 metres underwater. (The) blast would not propagate far enough to constitute a risk.”