SYDNEY, April 2 (Xinhua) -- An 18-year-old apprentice builder was killed when scaffolding collapsed at a Sydney construction site on Monday.

Another 39-year-old man was freed from the rubble and taken to hospital in a critical condition.

Eight ambulance, police, fire and rescue crews and a medical transport helicopter attended the scene which was littered with debris.

New South Wales Ambulance Acting Inspector Steven Vaughan described "an absolutely chaotic and emotionally charged scene... given the nature of the debris, the location of where it occurred and just the emotional state of all those who wanted to help their colleagues."

"It took some time to ascertain what had happened," he said.

The man killed in the incident had turned 18 only one week before and had been working on the site for over a year.

Construction industry union state secretary Darren Greenfield said there were others who had been on the scaffolding at the time but were able to get clear before the structure fell.

"We had a couple of members, bricklayers, up on the top of the scaffold about to start work and they jumped off onto the balcony as it started to move, so that saved their lives I'd say," Greenfield said.