Timor Sea gas rig liable to explode

A drilling rig disgorging oil and gas into the Timor Sea is not expected to be plugged for at least the next few days.

Gallery: See aerial pictures of the stricken rig

Spill zone a marine life "superhighway"

A 20km marine and air exclusion zone has been placed around the rig as the area is considered very hazardous and liable to explode.

The unmanned rig is spewing an unknown quantity of highly flammable gas into the atmosphere and weather conditions are preventing the gas from dissipating. Oil is still flowing from the leak into the marine environment.

The company at the centre of the leak, PTTEP Australasia, says it will pay all costs for the clean-up and has described the incident as "very regrettable".

PTTEP director and chief financial officer Jose Martins said the leak would not be plugged until a detailed report was completed outlining options for stemming the flow of oil and gas into the environment.

He said because of the danger currently posed by the high level of gas on the rig, no one was able to get aboard and assess the situation and it would be days before the situation was clarified.

A plume of white gas is clearly visible over the rig. The oil and gas is being drawn up the rig pipe from around 3500 metres below the sea bed.

"While the current primary focus was now on minimising environmental impacts - and that will continue - the major operational issue remains the leaking of gas and the fire risk which this involves," Mr Martins said.

"This risk means that at present we cannot safely get back on board the platform - so that option for bringing the leak under control is ruled out for now."

The Australian Maritime Safety Authority is battling to contain the spill off the Kimberley coast and says the remote nature of the location is hampering containment efforts.

Oil and gas started to leak from a drill hole in the sea bed early yesterday morning and continues to disgorge into the ocean.

The slick is eight nautical miles long and around 30 metres wide and is sitting off the mobile drilling rig at the centre of the leak, the West Atlas.

A Hercules aircraft from Singapore is scheduled to fly over the oil slick this afternoon in an attempt to drop a chemical dispersant to break up the oil.

PTTEP Australasia has handed control of the spill's containment and clean-up to the AMSA.

The leak began yesterday at around 5.30am prompting the evacuation of nearly 70 workers from the mobile drilling rig 250km north west of the Truscott Airfield in Western Australia and 690km west of Darwin in the Northern Territory.

Mr Martins said his company's first priority had been the safety of its workforce.

He denied reports that hydrogen sulphide had been detected on the rig prior to the evacuation saying there is no hydrogen sulphide in gas from the drilling area.

"We are encouraged by the preliminary scientific assessment of AMSA that the oil seems to be breaking up or evaporating at about the same rate than any leakage which is still occurring," Mr Martins said.

A spokeswoman for the AMSA confirmed that environmental officers had this morning determined that the spill was evaporating at a rate similar to the rate at which the oil was leaking into the ocean.

She said the spill was the biggest of its type in at least the past five years and the authority was concerned about its environmental implications.

"At least the leak does not appear to be growing," the spokeswomen said.

She said the oil looked like a light sheen on the ocean and did not appear at this stage to be heading towards the pristine Kimberley coast.

In a written statement this morning the AMSA said the leak had occurred "in one of the remotest locations possible, making any operation difficult."

"It is too early to determine the full impact of this incident," the statement said.

"AMSA is working with the company and has stressed the urgency to repair the well head and stop the oil flow and PTTEP has initiated actions to achieve this.

"Dispersant stocks (approximately 50 tonnes) have been deployed from the Australian Marine Oil Spill Centre by air ready for operations tomorrow. AMSA has sought assistance from Emergency Management Australia in the provision of transport and logistic support."

A spokesman for PTTEP said the company was working closely with the AMSA and the Australian Marine Oil Spill Centre.