Still no info on what caused it.
It is usually an incorrectly burning gas stove or appliance.
Instead of a blue flame it will look yellow.
https://www.abc.net.au/news/2025-09-16/nsw-sydney-riverstone-gas-leak-restaurant...One dead, seven hospitalised after gas leak at Sydney restaurant
By Courtney Barrett Peters
By Miriah Davis
Topic: Police
Tue 16 Sep

In short:
A 25-year-old man has died and several others are receiving medical treatment after a gas leak at a restaurant in Sydney's north-west.
Fire and Rescue NSW said "extremely high levels" of carbon monoxide were detected at the scene.
Hazmat response specialists have declared the scene safe and air quality samples will undergo further testing.
NSW Police Assistant Commissioner Gavin Wood said early indications suggested the deceased was employed at the restaurant as a cleaner.
"At that time the five police officers have attempted CPR on that male, to the point where they felt there was something a little amiss in terms of the environment they were in, including an odour," Assistant Commissioner Wood said.
A 25-year-old man has died and seven others, including police officers, have been hospitalised after a gas leak at a restaurant in north-west Sydney.
Emergency services were called to Haveli Restaurant in Riverstone about 9:15am on Tuesday after reports of a concern for welfare from the owner of the premises.
Two people were pulled from the building, one of whom was unresponsive and could not be revived, according to Fire and Rescue NSW (FRNSW).
NSW Police Assistant Commissioner Gavin Wood said early indications suggested the deceased was employed at the restaurant as a cleaner.
"At that time the five police officers have attempted CPR on that male, to the point where they felt there was something a little amiss in terms of the environment they were in, including an odour," Assistant Commissioner Wood said.i