Holes in European Legislation are to blame for the tide of toxic red mud that escaped an alumina plant in Hungary last week, according to an expert in mining policy. Some 700,000 cubic metres of corrosive mine tailings escaped a facility owned by MAL Magyar Aluminium when the concrete dam holding them back burst on 4 October. The mixture includes iron oxide, giving it the red colour, and highly caustic calcium oxide, or quicklime. Paul Younger of Newcastle University, UK, says the sludge would not have escaped if the facility had a second, back-up wall. This is standard practice around the world for the industrial storage of many hazardous materials, but European Union legislation does not require it for mine waste. "The mining industry in Europe has been brilliant at avoiding regulation," Younger told New Scientist "This is the result." The sludge flooded several towns in north-west Hungary, killing at least eight people and injuring more than 100. It has also entered the local river Marcai, apparently killing all wildlife, and has now reached the Danube. "The good news is it needn't be a long-term problem," says Tom Dyer, a civil engineer at Dundee University, UK. Relief workers are tipping gypsum and fertiliser into the mud to neutralise the alkalinity. As New Scientist went to press, engineers were building an emergency wall, after new cracks were discovered that threaten to cause a second spill.