An investigation has been launched at chemical factories following a leak on Thursday, according to the local government.

The campaign, targeting all chemical manufacturers in the city, was launched on Friday to further ensure "production safety," Qiu Chuanghong, a spokesman for Guangzhou municipal government, said in an interview with China Daily.

The liquid chemical leak occurred at the Guangzhou Titanium Dioxide Factory on Thursday afternoon, forcing more than 200 nearby residents to be evacuated.

"There have been no reports of casualties so far," said Qiu, adding that only a fire fighter and a worker at the factory had been injured.

Both were sent to hospital and are now in a stable condition, according to the spokesman.

The local government organized a special emergency team, formed by work safety, health and environmental protection departments to investigate the cause of the leak.

The investigation found that the leak was caused when machinery was dismantled, according to Su Zhequn, vice-mayor of Guangzhou, capital of South China's Guangdong Province.

The factory, a subsidiary of the Guangzhou Chemical Group, closed last year and sold its equipment to a Jiangmen-based hardware factory.

"An initial investigation shows that the leak was caused by the improper removal of equipment by workers. Further investigation will be conducted in line with the inspection campaign at chemical factories," Su said.

The campaign, launched by the local work safety department, will mainly focus on chemical products and those factories that have been closed.

According to Su, a white acrid mist was produced during the leak.

The environmental protection department set up six monitoring centres in the factory, but found that the toxic mist did not reach a hazardous level and would not affect people's health.

"The leak will also not affect the Pearl River, although the factory is situated very close by," Su told reporters on Friday.

However, residents nearby were still not allowed to return to their homes as of Friday afternoon, sources with the local government said.

Editor: Yan