Rain fell Tuesday on the remains of a Chinese industrial site devastated by giant explosions, complicating clean-up efforts and heightening fears about toxic contamination as ceremonies were held to mark the disasters 114 deaths. Around 700 tonnes of highly toxic sodium cyanide were at the site in the northern port of Tianjin, officials say, and water could disperse it more widely. It could also disperse chemical residues on the ground into the air when it evaporates, and some of the many substances on the scene could react with it. Officials have insisted that the city’s air and water are safe, but locals and victims relatives have voiced scepticism, while international environment group Greenpeace has also urged transparency. Out of 40 water testing points, eight showed excess levels of cyanide on Monday, all within the cordoned-off area and the highest 28.4 times official standards, said Bao Jingling, chief engineer at the Tianjin environmental protection bureau. The chemical had been detected at another 21 points, he added. Authorities have built a dam of sand and earth around the blasts’ central 100,000-square-meter “core area” to prevent pollutant leakage, Bao said, and drained water from pits and pipelines to make space for the rain.