Two planes were given permission to dump four weapons on
the marine park after a mission to drop them on a bombing range on a nearby
island had to be aborted.

The incident took place during joint US-Australian exercises
over central Queensland last Tuesday.

The US 7th Fleet said in a statement that the bombs were
jettisoned in more than 50 metres of water, “in a deep channel away from
the reef, to minimise the possibility of reef damage”.

But conservationists were furious, with Larissa Waters, a
Queensland senator with the Australian Greens party, calling the incident
“outrageous”. “I mean, have we gone completely mad?” she
asked. “Is this how we look after our World Heritage area now? Letting a
foreign power drop bombs on it?”

The two AV-8B Harrier jets from the 31st Marine
Expeditionary Unit were supposed to drop the bombs on the Townshend Island
range, but air traffic controllers reported “hazards” in the area,
and after several unsuccessful attempts the pilots aborted the mission.

The jets – which were launched from the aircraft carrier
USS Bonhomme Richard in the Pacific Ocean – jettisoned the weapons because they
were low on fuel and could not land with their bomb loads, according to the US
Navy statement.

It said there was no danger to shipping or navigation.

The incident happened on the second day of the biennial
joint military exercise, named Talisman Sabre, which  involves about 28,000 personnel over three
weeks. The bombs each weighed 226 kilos, according to the US TV network NBC.

US and Australian authorities have embarked on an
investigation.

The Barrier Reef – the world’s largest coral reef,
stretching 2,600 kilometres along Australia’s east coast and rich in marine
life – is already vulnerable thanks to warmer seas, industrial port development
and pollution run-off from farms.

The UN body UNESCO has warned Australia that the reef
will be listed as threatened unless steps are taken to protect it.