At least nine people have died and 30,000 are living in temporary shelters after chlorine gas explosions rocked the industrial city of Chongqing in southern China. This is the same area where a gas leak killed more than 230 people last year.

Xinhua, China's official news agency, quotes the head of the technical team at the scene of the explosion as blaming the accident on outdated equipment and carelessness by the workers, who he said were likely trying to speed up the process used to create liquefied chlorine gas. Chlorine gas is extremely poisonous if inhaled.

Xinhua said leaks were first detected Thursday night in all seven of the plant's chlorine gas containers. Then, on Friday night, a series of powerful explosions occurred at the plant, killing eight managers and one worker.

The news agency said 150,000 residents were initially evacuated from their homes, and 30,000 of those spent Friday night in temporary shelters.

Rescue teams wearing protective gear have now sealed off the plant, and on Saturday, city officials were attempting to reassure residents that Chongqing's water and air supplies had returned to normal.

The news agency said this was the third time in a year that there have been gas leaks at the plant.

Last December, an explosion in a gas field near the city created a poisonous cloud that killed more than 230 residents.