A man has been pulled from the rubble of an apartment complex following what is believed to be a gas explosion in Sydney’s west.

The blast blew out a wall and significantly damaged the second level of the three-storey unit block in Lidcombe about 6.30am on Friday.

More than 50 firefighters and 16 fire trucks, as well as police, responded to multiple emergency calls after the explosion on Clarence Street.

Adjoining units and a car were also damaged.

Firefighters found a 40-year-old “unconscious or semiconscious”. He was treated by paramedics and taken to Westmead Hospital for treatment to burns to his face and hands.

Another man, aged in his 60s, was also taken to Auburn Hospital to be treated for smoke inhalation.

“They tell me that they’ll be OK,” FRNSW superintendent Adam Dewberry said.

The blast blew out a wall of the apartment block, and a car was also damaged. Photos: Fire & Rescue NSW/ABC News

A further 40 people were evacuated from the six-unit complex. Seven people were assessed by paramedics.

Everyone inside the building had been accounted for, Dewberry said.

“Our efforts will start to commence soon about getting some of their essential stuff such as medications … there are some pets left in the building,” he said.

“A number of … people will be displaced and will not be able to go back into their accommodation due to the damage to the structure.”

Firefighters isolated gas and power supplies as crews used gas detectors to detect any ongoing hazards.

The cause of the explosion remained a mystery on Friday afternoon, although gas is the prime suspect.

“It was like ‘boom’, something blasted,” resident Puja Shrestha told the ABC.

“Everyone was shouting, ‘Let’s go, out, out, out’. We looked around, grabbed our phones and laptops.

“We were shocked … how could it happen?”

Engineers and specialist FRNSW technicians remained on the scene into Friday, using laser monitoring equipment to check for movement within the building.

Some residents were permitted to return later on Friday. But the block remained off limits amid fears for its structural integrity.