A solar panel factory in eastern China has been shut down after protests by local residents over pollution fears.
Some 500 villagers staged a three-day protest following the death of large numbers of fish in a local river.
Some demonstrators broke into the plant in Zhejiang province, destroying offices and overturning company cars before being dispersed by riot police.
Tests on water samples showed high levels of fluoride, which can be toxic in high doses, officials said.
The BBC's Juliana Liu in Shanghai says the Chinese villagers see the plant's closure as a victory.
They accuse Jinko Solar, a Chinese company making solar panels for sale overseas, of dumping hazardous chemicals into the water supply, our correspondent says.
"We feel that it is socially responsible to close the factory first and to take corrective measures," company spokesman Thomas Jing told the BBC.
He said there had been accidental discharge into the surrounding area during a rainstorm at the end of August.
He said chemicals used at the factory had been stored in an open area rather than a warehouse, and that the covering had been ripped off during the unexpectedly harsh weather.
Mr Jing said the firm was investigating whether the fluoride was responsible for the death of the fish. A clean-up was also under way, he said.
The firm in Haining city is a subsidiary of a New York Exchange-listed Chinese solar company, JinkoSolar Holding Company.
Meanwhile, local government officials said there would be an overhaul of the production procedures at the plant involving the emission of waste gas and waste water.
"[We will] go all out to maintain stability and seriously deal with those who are suspected of violating laws in the incident in accordance with the law," Haining's city government said in a statement.
It also reported police had arrested a man for spreading "rumours" on the internet about cases of leukaemia and other cancers in local residents.
Chen Hongming, a deputy head of Haining's environmental protection bureau, was quoted by Chinese media as saying that the factory's waste disposal had failed pollution tests since April.
The environmental watchdog has warned the factory, but it had not effectively controlled the pollution, he added.
Government officials have been sent to the area to hear local residents' grievances, the China Daily reported.
This is the latest example of Chinese citizens being spurred to action over environmental worries. Last week, Shanghai halted production at two factories over worries about lead poisoning.
Last month, a chemical factory in the north-eastern city of Dalian was ordered to move after 12,000 residents took to the streets over pollution fears.