A major blackout that wreaked havoc during rush hour in Australia's largest city has exposed a flaw in the city's terrorism warning system, the government acknowledged today.
A network of loudspeakers designed to alert people during emergencies has no battery backup, said New South Wales state Emergency Services Minister Steve Whan, which would render it useless if there is a total power failure.
"There may be a need now to talk to my Cabinet colleagues and others about whether or not some other sort of upgrades are needed to the system," Whan told reporters in Sydney.
The loudspeakers were not activated in downtown Sydney during Monday's chaotic two-hour power outage, which dimmed traffic lights, caused gridlock on the roads, trapped office workers in elevators and left 70,000 homes and businesses in darkness.
Deputy New South Wales Police Commissioner Dave Owens said the warning network was not activated because it was designed primarily to evacuate people, but that the system would have worked on Monday because it is powered by five separate electricity substations — and not all were affected by the power outage.
The network of 98 loudspeakers and 13 messaging signs was installed in 2007 as a mode of communicating with residents during a terrorist attack or other emergency. The speakers emit a wailing siren to attract people's attention, followed by a police announcement directing people to evacuation points plotted around the downtown area.
The effectiveness of the system has been questioned in recent months after some of the alarms failed to sound during test runs and many people complained they couldn't hear the warnings.
Owens said he authorized police to send out text message alerts to around 2,400 building managers and fire wardens.
However, the alerts were not sent out until 40 minutes after the power was cut. By that time, most office workers who weren't trapped in high-rise elevators had already evacuated their darkened buildings.
"I believe 40 minutes was an acceptable time," Owens said. "I believe our response to the power outage was appropriate and, in fact, we had police on point duty within minutes of the blackout."
Police will conduct a review of the response, he said.
Opposition spokesman Duncan Gay criticized the government's response to the blackout, saying it made Sydney a more vulnerable terror target.
"I'm sure if people are looking for likely targets this pushes us slightly further up," Gay said.
Power supplier EnergyAustralia said the blackout occurred when four power cables that supply two major substations in central Sydney failed.