A major gas leak in central Dunedin - which could have been ''catastrophic'' - prompted the evacuation of people from shops and businesses yesterday morning.
Contractors digging at a construction site in Albion Lane ruptured a reticulated gas main about 8.45am.
All buildings in the block bordered by Albion Lane, George St, St Andrew St and Great King St were evacuated for more than two hours.
Willowbank Senior Station Officer Craig Geddes, the officer in charge of the incident, said any spark or ignition could have caused an explosion.
''It certainly had the potential to be catastrophic and that's why we had to evacuate the area,'' he said.
''The gas line was ruptured completely so there was a fair bit of gas.''
Liquefied petroleum gas (lpg), which is heavier than air, spread under the floor level of the Harvest Court Mall and accumulated at the lowest point - a room containing electrical wiring and equipment.
Willowbank and St Kilda firefighters were guided by Nova Energy staff, who used gas detectors to identify the concentration of gas and isolate it.
''The Nova guys were fantastic.
''They shut down the main supply from George St and then it was just a matter of us dispersing it.
''We set up a fan to push the gas into the open air so it dispersed at safe levels,'' Mr Geddes said.
Gas readings were taken every 15 minutes and the cordon was lifted after 11am.
A small cordon around a switchboard remained for a couple of hours to allow monitoring, Mr Geddes said.
''We take any incident like this very seriously.''
The disruption was just a part of being a business owner, McDonald's franchisee Justin Stonelake said.
His George St restaurant was among the many businesses evacuated and closed.
Mr Stonelake said Monday mornings were not typically busy and the loss in business was a ''minimum disruption''.
''It could have been a lot worse, and thankfully, all our staff and customers are safe and well,'' he said.
John Clearwater Contracting staff who struck the gas line were working on a development being managed by Arrow International on behalf of the property owner.
Arrow International southern strategic development manager Stephen Cairns apologised for the inconvenience and said the company's insurance agents would deal with any claims.
Mr Cairns said workers had the appropriate site plans and were briefed on the job, and it was not clear whether the gas pipe was ruptured as a result of human error or if the pipe was not located as shown in plans.
''Unfortunately, accidents do happen,'' he said.
