A 200-metre exclusion zone was put in place in Fyshwick on Monday afternoon after construction workers dug into a pressure pipe, causing a "massive gas cloud".
Subscribe now for unlimited access.
$0/
(min cost $0)
or signup to continue reading
The gas pipe was a ruptured outside the front of The Canberra Times building on the corner of Newcastle and Pirie streets and forced around 100 people to clear the area, as emergency services personnel feared an explosion.
The exclusion zone also blocked traffic on Newcastle and Pirie streets until 2.30pm.
The Canberra Times and nearby buildings were evacuated after ACT Fire and Rescue were alerted to the incident by an emergency triple zero call from a member of staff at the newspaper about 11.45am.
ACT Fire and Rescue commander Danny Brighenti said construction workers had dug into a 100 millimetre AGL pressure pipe which caused the huge gas cloud.
"We've done monitoring and there are high readings of gas in the immediate area," he said in the early afternoon.
"We've put water fogs onto the gas to dissipate it into the atmosphere. At the moment, the contractors have dug holes, we've just about to put hydraulic plants in there to cut supply off.
"We're hoping when it's clamped it will stop the immediate threat however we have gas in the storm water system so we've got to monitor that and allow that to ventilate so when we allow traffic back in we don't find the ignition source.
"[An explosion] is our biggest fear. That's why we've put the exclusion zone in to stop ignition sources being brought into the area but at this point it's dissipating quite well and we don't think it will take too long after the gas has been clamped off to make it safe.
"A 100mm main, that's a lot of gas under a lot of pressure and it creates a lot of cloud.
"Luckily natural gas is lighter than air and it goes up into the atmosphere quite readily but if an ignition source [is in the area it] may cause an explosion.
"WorkCover have been notified ... if it's a workplace accident it will be investigated by WorkCover no doubt."
Gas contractors had to dig holes on either side of the ruptured section of pipe then use clamps to cut off the gas supply.
Firefighters dissipated the gas into the atmosphere while the HAZMAT crew carried out atmospheric monitoring, the Emergency Services Agency said.
The exclusion zone blocked access to Pirie Street at both entrances; Newcastle and Barrier Streets and ACT Policing diverted traffic in the area
Firefighters continued atmospheric monitoring and dissipating gas into the atmosphere until shortly before 3pm.
"All our monitoring has been undertaken, there is a smell in the Canberra Times but we're mechanically ventilating that and those readings are zero. They're all zero readings [down the storm water drain too]," Mr Brighenti said as staff were allowed to return to the building.
"Obviously the contractors have to repair the damaged pipe so there will be some work around at the time but we're hoping that traffic will be opened up and the public will be able to utilise those areas again."
The gas supply to businesses on Pirie Street will remain shut off while the break in the line is repaired.
"These are on ring mains, they have to be clamped to both sides, so most of the other services in the Fyshwick area will still have gas, it's only the immediate areas either side of the clamping that will have, only two or three businesses will be without gas for a short period of time," Mr Brighenti said.
