An ammonia gas leak at a chemical fertilizer factory in central China killed one worker, injured six people and forced the evacuation of about 20,000 residents.

The gas leaked out of a broken pipe in a nitrogen fertilizer factory in Dawu county, Hubei Province on the morning of 1 November, according to Chen Yixin, assistant general manager of the Huangmailing Phosphorous Chemical Industry Group Company, which owns the factory.

One factory worker died at the site. Three other factory workers, a fire-fighter, a 16-year-old female student and a pregnant woman in a nearby village were critically ill.

Chen said workers closed the valve of the pipe to stop the leak about one hour after the accident, but 10 tons of ammonia gas had already come out.

Schools and houses nearby were immediately evacuated while fire-fighters sprayed water into the air in shifts to clear the gas, but the smell of ammonia still lingered in the air at the factory on the evening of 1 November.

However, the water flowed into the nearby Huanhe river, resulting in temporary "super-high" levels of ammonia and nitrogen and threatening water supplies downstream, according to Xinhua News Agency.

Dawu county environmental protection authorities said the levels of ammonia and nitrogen had dropped by the afternoon of 1 November, and the residents were returning home that evening. The cause of the incident is being investigated.

Sources: Xinhua News Agency (1 November 2006), Agence France-presse (1 November 2006), Associated Press (1 November 2006)

2 November 2006