A dozen shipping containers filled with hazardous chemicals were dropped into the Yangtze River near Yichang, Hubei, east of the Three Gorges. The city's water supply was temporarily cut off following the accident on Monday night, but officials insisted to local media yesterday that no chemical spillage had been detected downstream. The Three Gorges Daily reported that the local government had dropped the emergency environmental warning at 4pm yesterday. The paper said all 12 hazardous containers had been located and three had been removed. The 12 containers were among 62 that fell from the 3,000-tonne Hanglong 518, registered in Chongqing, which had been carrying 176 containers when the accident occurred near Shipai town, upriver of Yichang, late on Monday night, state media reported. Six contained potassium permanganate, one contained sodium permanganate and the others contained potassium hydroxide. Potassium permanganate and sodium permanganate are powerful oxidants, often used as sterilising agents. Potassium hydroxide, also known as 'caustic potash', is a strong alkali often used in bleach. All three chemicals are water soluble and dangerous in high concentrations. The permanganates are highly toxic to fish, less so to people. An initial investigation by the Sanxia Maritime Safety Administration had determined that the containers fell overboard after the ship performed an 'inappropriate manoeuvre' by 'blindly increasing speed' while turning in fast-flowing waters, Xinhua reported. Officials at both the Yichang Environmental Protection Bureau and the maritime safety administration said they could not give details without authorisation from the Yichang government information service. A spokesman for the information service denied all knowledge of the incident. 'I cannot make any comment until an official statement has been issued,' he said. Xiang Chun, an environmental activist with the Green Volunteers' Union of Chongqing, said he was deeply concerned about Monday's incident. 'This is the flood season, so the waters are very high and fast-flowing,' he said. 'This means it will be very difficult for them to recover all the containers. 'I believe there is a high risk of chemical spillage. 'I have heard of many ships losing shipping containers in the Three Gorges area over the years, but this is the first time I've heard about one losing so many that contained hazardous chemicals. It is very worrying.'