A cocktail of 650 tonnes of fuel and fertiliser has been lost from a cargo ship caught in fierce seas from Cyclone Hamish off the southeast Queensland coast, potentially threatening wildlife.
Up to 30 tonnes of oil spilt into the sea off Moreton Island on Wednesday morning, after 31 shipping containers carrying 620 tonnes of ammonium nitrate fell overboard at 3.15am (AEST), damaging fuel stores in the hull of the Pacific Adventurer.
Aerial reports estimate the oil slick covers three nautical miles by 500 metres and is drifting in a northwesterly direction.
Maritime Safety Queensland (MSQ) general manager Captain John Watkinson told reporters the 180-metre ship and its 15 crew - who had left Newcastle on Tuesday afternoon bound for Brisbane - had anchored in calmer water in Moreton Bay for safety precautions and assessment.
Chance of explosion \'low\'
Capt Watkinson said although about one tonne of the fertiliser, which can be used to make explosives, was also covering the ship\'s deck, the chance of an explosion was low.
"The cargo is rather benign. It takes a significant mixing with certain other contaminants, which are not on the ship, or a pretty big ignition source and neither one are present," Capt Watkinson told reporters in Brisbane on Wednesday.
"We believe the risk is pretty low."
But as a precaution, emergency services crews had assessed the ship and were also preparing to be on standby when it was expected to dock in Brisbane on Thursday morning.
MSQ had so far been unable to locate any of the shipping containers and the best outcome would be for them to wash ashore, Capt Watkinson said on Wednesday afternoon.
The Environmental Protection Agency (EPA) said the oil spill could potentially kill any wildlife that it came into contact with.
The ammonium nitrate, which can be explosive when exposed to heat or chlorine, should dilute enough to not cause any major problems except algal blooms, EPA incident response adviser Mike Short said.
"The oil is our greatest concern, both to the environment and wildlife," Mr Short said.
"Spills and wildlife don\'t mix."
Mr Short said crews were patrolling Moreton Bay and Bribie Island for signs of oil on the beaches and for injured wildlife.
Circumstances of spill unclear
It was still unknown how the containers had come loose, but Capt Watkinson denied the containers were unlashed by the crew when they struck rough water.
It was likely the force of the weather broke the bindings, he said.
"Whatever hit the ship at the time carried a fair bit of force to knock 31 containers off the deck," Capt Watkinson said.
MSQ had issued alerts to all vessels to look out for any containers that may be floating in the water.