One hundred and sixty-four people poisoned by chlorine had been sent to hospital by 8 a.m. Monday in Yinchuan, capital of the Ningxia Hui Autonomous Region, where liquefied chlorine gas leaked out from a chemical company on Sunday evening.

Medical workers carry out emergency treatment on patients poisoned by leaked chlorine at a hospital in Yinchuan, Northwest China's Ningxia Hui Autonomous Region July 10, 2006. More than 164 people fell ill after a chlorine leak at a chemical company in Yinchuan. [Xinhua]

Yao Chengli, president of the Yinchuan No.1 People's Hospital, received a phone call at 9 p.m. Sunday, in which the caller suspected that the pungent smell in the air of the Xixia district of Yinchuan could be chlorine. An ambulance hurried to the spot. One patient is seriously poisoned.

A medical worker carries out emergency treatment on a patient poisoned by leaked chlorine at a hospital in Yinchuan, Northwest China's Ningxia Hui Autonomous Region July 10, 2006. More than 164 people fell ill after a chlorine leak at a chemical company in Yinchuan. [Xinhua]

Urban population in the Xixia district is 210,000.

According to authorities, the rust pipe in the Xin'erte Chemical Company cracked, which led to the leakage.

Quantity of the leakage, affected population and its cause are still under investigation.