More than 100,000 residents of central China's Yueyang county are being warned not to drink tap water, after environmental officials found high levels of arsenide in the water supply.
China's official Xinhua news agency says environmental officials found the level of arsenide in the Xinqiang River was 10 times higher than "official" standards during a routine water quality check Friday.
Xinhua says a chemical plant in Linxiang City, 50 kilometers upstream, polluted the river. The factory has been closed.
Authorities increased the amount of water flowing from the Tieshan Reservoir Saturday to help dilute the river. Fire trucks are distributing drinking water, and authorities have allowed some people to use underground water sources.
Arsenide is a compound of arsenic, a colorless, tasteless poison. It can cause vomiting, lung cancer, and in some cases, death.
China is struggling to balance its booming industrialization with environmental protection. Chemical spills and other pollution caused by industrial mismanagement in recent years have tainted water supplies serving millions of Chinese.
Some information for this report was provided by AP and AFP