An exclusion zone was established around the Banksmeadow plant on Tuesday after a fire sparked fears a cooling tower could collapse onto stores of highly-flammable hydrogen.
Fire and Rescue NSW crews safely removed six trailers, each with 1700 cubic metres of the potentially-explosive material, by rigging them one-by-one to a tractor unit and towing them to safety.
Once the gas had been removed, an earlier precautionary evacuation notice was withdrawn for residents and workers within 800 metres of the site site in the Bayside area, between Hillsdale and Banksmeadow.
A smaller exclusion zone was established around the tower while the risk of collapse remains.
The blaze broke out at the plant just after 6am on Tuesday, with arriving crews spotting flames 50 metres above a 70-metre tall exhaust stack.
Staff had shut down the plant and were carrying out a controlled burn inside the stack to halt the flow of gas, Fire and Rescue NSW said.
However, further alarm was raised later in the day when crews were called back to the tower over concerns one of the cooling towers had suffered structural damage, and was at risk of collapse.
"There are now concerns the tower may collapse and, if it does, land on a supply of highly flammable hydrogen, being stored on semitrailers on an adjacent property," Fire and Rescue said in an earlier statement.
Significant resources were sent to the scene including local firefighters, HAZMAT crews, the Environmental Protection Authority, Safework NSW, NSW Police, paramedics and experts in structural collapse.
Drones are also being used to monitor the structural integrity of the tower.
Control of the site was handed back to the company.
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