Internal documents show BP would have to transport a containment response system 14,000km in the event of a spill in the Great Australian Bight

BP’s attempts to halt any oil spill from planned drilling off South Australia’s coast would depend on transporting recovery equipment from Houston, Texas, internal documents have revealed.

In information submitted to the federal government, BP says equipment to cap leaking oil wells is based in Singapore, more than 4,800km away, while a containment response system would have to be transported from Houston in the US, more than 14,000km away.

The shipping and installation of the equipment from Singapore to Australia would take 32 days, while the response system would take 25 days to arrive from Houston, the document shows. In the event of a disaster, a second rig would be positioned to drill a “relief” well, which would take 157 days, BP says.

BP, which plans to drill a series of exploratory wells in the Great Australian Bight marine park from next year, says it would take 35 days to cap a leaking well in a “worst credible case scenario”.

However, government officials told a BP representative this scenario was “optimistic” due to the deep water and rough seas faced by any recovery team tackling an oil spill, according to minutes taken from a phone briefing.

The government officials also stated they “normally expect more detail around response measures, for example equipment availability”.

The Wilderness Society has called for an end to BP’s ambitions in the Great Australian Bight, which it calls “one of the last pristine marine environments left in the world”.

The area’s ecosystem is an important foraging and calving habitat for blue whales and southern right whales. Seal lions, sharks and shearwaters are also in the region, although BP says only the shearwaters will be in the vicinity of the drilling sites, located around 300km off the South Australian coast.

“The Bight is one of the most significant whale nurseries in the world, it’s a marine wilderness that’s never been industrialised,” said Peter Owen, director of the Wilderness Society’s South Australia office.

“Of all the places to be turning into an oil field, the Great Australian Bight is not it. This is akin to what Shell is trying to do in the Arctic – it’s utterly inappropriate.”

Despite holding consultations with groups over the drilling, BP has yet to release an oil pollution emergency plan, which would shape its response should there be a disaster similar to the Deepwater Horizon explosion in the Gulf of Mexico in 2010, which killed 11 people and spilled 4.9 million barrels of oil into the ocean, injuring or killing thousands of birds, sea turtles and dolphins.

In estimates shown to the government, BP states a worst case oil spill could cover an area of 175km by 200km, with a 7% chance the oil would reach Kangaroo island. Without a response, as much as 805 metric tonnes of oil would hit around 100km of coastline, around 19 days from the initial spill.

The oil would potentially cause “minor skin irritation and ingestion” for marine animals, BP’s submission states. BP predicts the nearest whale foraging site would be 8km from the drilling site, although a presentation given to environment groups states the whales would be 150km away while the environment groups themselves claim the areas actually overlap.

A spokeswoman for BP said the company has plans for a “range of credible spill scenarios”.

“Oil spill response plans are designed to be scaled up or down as required,” she said. “The global industry holds equipment that is accessible to BP in a number of locations – this is best practice for the industry.

“BP has its own high standards and requirements for safe operations that incorporate what we have learned over many years of operation, and specifically from the Deepwater Horizon accident.”

The spokeswoman said its environment plan, which includes its emergency response, will be submitted “in the middle of this year”.

The Wilderness Society’s Owen said: “The oil industry always says it has learned its lessons and then ‘bang’.”

“The Great Australian Bight is one of the roughest, most remote places on the planet. The Gulf of Mexico spill took 87 days to plug and that was on the doorstep of the oil industry, with all their infrastructure there. The conditions would be far more challenging if something went wrong here.”

BP was first granted its South Australian exploration area in January 2011, just eight months after the Deepwater Horizon disaster.

The British oil giant initially planned to drill four exploratory wells by 2017, with a further six wells by 2020, in an attempt to find what could be vast oil reserves in the Ceduna basin system that lies beneath the waters of the Great Australian Bight. Norway’s state oil company Statoil has a 30% stake in the venture.

However, BP now forecasts it will only be able to complete two of these wells – the first being in waters 2.2km deep – by June 2017 and will need more time for the remaining wells.

The exploratory drilling plan will have to be approved by the National Offshore Petroleum Safety and Environmental Management Authority before proceeding. A Nopsema spokesman said the body could only accept or reject BP’s plan, rather than amend it. It will have 30 days to make a decision after the plan is submitted.

A total of 15 exploration wells are planned for the Great Australian Bight, with Santos, Chevron and Murphy Oil all holding permits near BP’s site. BP is the furthest advanced with its drilling plans.