Workers evacuated following gas leak in Sydney tunnel

gas leak
Construction of Westconnex in December 2017. Image: Rose Marinelli /

Hundreds of construction workers were forced to evacuate a WestConnex road tunnel on Monday morning (Dec 17) following an unidentified gas leak, with fears workers were at risk of an explosion or asphyxiation in the confined tunnel.

The Electrical Trades Union was notified by evacuating members at approximately 9.30am following reports that the gas had been detected around the Parramatta Road on and off ramps, along with nearby tunnel sections.

The union said the incident was the second time in less than a week that gas leaks had forced the evacuation of the same section of tunnel, yet project management — a joint venture consisting of CPB Contractors, Samsung C&T, and John Holland — were still unable to identify the source of the gas or how it is entering the tunnel.

Gas distributor Jemena was called in to examine the tunnel on Thursday, December 13 following the first incident, which occurred at approximately 11am, but were unable to ascertain whether the gas was originating from nearby mains.

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ETU secretary Justin Page said the union had serious concerns for the safety of workers in the tunnel.

“Gas leaks pose a significant threat to health and safety, particularly as the gas could be ignited by machinery operating in the tunnel, causing an explosion,” Mr Page said.

“We are demanding that workers not be sent back into this section of the tunnel until the source of this gas leak is identified and remediated, particularly as it has now occurred twice in this same section of tunnel.

“We are also deeply concerned by reports from our members that management failed to notify the safety regulator, SafeWork NSW, of the first gas leak as they are legally required.”

Mr Page said the dangers posed by gas leaks were amplified in tunnels, where a lack of ventilation could allow the gas to build up to dangerous levels.

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“We are insisting that project management implement 24-hour air monitoring in all the WestConnex tunnels to ensure any future gas leaks are immediately identified, workers removed from affected areas, and the source of leaks addressed,” he said.

“Our members have previously raised concerns about inadequate ventilation in the tunnels, which has seen them exposed to poor air quality as dust and diesel fumes build up to dangerous levels. It is for this reason that we also believe management should move to immediately limit the number of diesel vehicles operating in the tunnel.

“SafeWork NSW need to urgently investigate the air-quality issues in these tunnels, in particular management’s apparent failure to report the first gas leak and the decision to send workers back into this section of the tunnel despite failing to identify the source of the leak or take steps to stop it.”

A spokesperson for SafeWork NSW said, “SafeWork has been in contact with WestConnex about an odour that has been identified in a section of the tunnel on Monday.

“The area has been evacuated. WestConnex continues to work with experts to try to identify the source of the odour.

“A SafeWork inspector will be also attending the site.”

Jemena was contacted for comment.