Thirty-nine people are ill -- seven of them critically -- after a toxic chemical leak in Wuhai City, north China's Inner Mongolia Autonomous Region, on Monday.

It was the region's third chemical leak in a week, a spokesman with the regional safety administration bureau said on Monday.

The workers were poisoned by the chlorine, a poisonous yellow-green gas with a pungent irritating odor, at around 1 a.m. when they were working in the Wuhai Municipal Chemical Co. Ltd., he said.

Fire fighters had evacuated 218 workers and residents nearby.

The cause of the accident is under investigation.

Chlorine leaks were reported on Friday and Saturday in Inner Mongolia Yili Chemical Industry Co. Ltd. in Erdos city. A total of 19 workers were poisoned, and 14 are still in hospital. Their conditions are described as stable.

No fatalities have been reported in the three cases.

(Xinhua News Agency March 25, 2008)