A statement from Chevron Australia described the leak as minor, saying it was detected on piping associated with the dehydration unit on the Train. 

Train 1 was shuttered in a controlled manner to isolate the area where the leak was identified as a precautionary measure, the statement said.  

"We are preparing plans for investigation and repair," a Chevron spokesperson told Energy News.

"Appropriate safety measures are in place to keep our workforce safe."

"Trains 2 and 3 remain operational and we continue to deliver LNG to customers and natural gas to the Western Australian domestic market."

Energy News understands that it is too early to determine how long the Train will be out of action, given that workers will need to depressurise the dehydration unit, which removes water from the gas stream prior to being converted to LNG. 

Scaffolding will then need to go up so the unit can be properly examined before a plan of action can be determined, according to sources. 

Inspectors from the WA Department of Mines, Industry Regulation and Safety (DMIRS) were coincidentally on site when the leak was discovered, carrying out routine inspections.  

"Chevron Australia has advised DMIRS that it discovered a minor issue at its Gorgon LNG plant during operations," DMIRS dangerous goods and petroleum safety director Steve Emery told Energy News. 

A spokesperson from the Australian Manufacturing Workers Union told Energy News that the union was investigating.  

AMWU state secretary Steve McCartney has been a vocal critic of Emery in the past, saying he was "too soft" on Chevron when cracks were found on the propane heat exchangers on Train 2 last year.  

The discovery forced the company to complete a staged shutdown of all the facility's trains over a period of six months from August last year.  

The three-train, 15.6 million tonne per annum LNG facility is operated by Chevron, with ExxonMobil, Shell, Osaka Gas and Tokyo Gas all having minor shares.  

In July Chevron made final investment decision on the US$4 billion Jansz-Io compression project to maintain gas supply at Gorgon. 

Construction and installation activities are expected to take approximately five years to complete, with work to begin in the second half of 2022. 

The leak follows news last week that Chevron will buy 5.23 million tonnes of carbon offsets and invest A$40 million in lower carbon projects in WA after its Gorgon CCS project, designed to capture and store CO2 from the LNG facility, failed to reach nameplate CO2 injection rates.