Tianjin port explosions (2015)

Ruihai Logistics, a private company set up in 2011, ran a 46,000 m² depot for hazardous chemicals in the port of Tianjin. According to Wikipedia it had operated without a valid licence from October 2014 to June 2015, and there were residential blocks less than a kilometre away. On the evening of 12 August 2015 a fire broke out; two explosions followed 33 seconds apart, the second caused by the detonation of about 800 tonnes of ammonium nitrate. The investigation, concluded in February 2016, traced the ignition to an overheated container of dry nitrocellulose. There were 173 dead, 104 of them firefighters, and 798 injured.

The depot held at least 700 tonnes of sodium cyanide. Cyanide was found in the sewers and in water on the site: on 17 August up to 28.4 times the limit, on 20 August up to 356 times at one point inside the alert zone. Outside the zone, 6 of 16 measuring points detected cyanide, within the limits (Voice of America, 20 August 2015). With the first rain a white foam appeared in the streets, and thousands of dead fish washed up 6 km from the site; the authorities put the die-off down to lack of oxygen.

The contaminated water was held on the site: the crater alone contained about 40,000 tonnes of it. The cyanide was neutralised with hydrogen peroxide. The State Council investigation held 20 companies and 171 individuals to account; in November 2016, 49 people were sentenced, 25 of them public officials.