Workers remove gypsum and mud from areas affected by the red mud spill. On 4 October 2010, a sludge reservoir in an alumina plant reservoir burst, pouring about 1 million m3 red mud into nearby villages. (Photo: WHO/Roger Aertgeerts)

The red mud spill in Hungary received a lot of media attention. (Photo: WHO/Roger Aertgeerts)

Experts from the WHO mission visit the recovery reservoir after the red mud spill in Hungary. (Photo: WHO/Zsofia Pusztai)

The spill may have resulted in widespread contamination of the environment, including air, water, soil and food in the affected area. The mud is being removed from agricultural soil. The fruit and vegetables grown this year in the affected area have been damaged and will not enter the market. Operations to clean up and rehabilitate the area will take several months to complete. (Photo: WHO/Roger Aertgeerts)

Hungary sampled river sediments to measure water quality in the area affected by the red mud spill. (Photo: WHO/Roger Aertgeerts)

A worker cleans a flooded house in Devecser, one of the Hungarian villages affected by the red mud spill, with a high-pressure water hose. (Photo: WHO/Roger Aertgeerts)

Workers remove the mud and gypsum outside a flooded house in Devecser, one of the Hungarian villages affected by the red mud spill. Gypsum was spread to reduce the corrosive effect of the mud. (Photo: WHO/Roger Aertgeerts)

WHO mission visiting Kolontar, the Hungarian village most affected by the red mud spill. (Photo: WHO/Zsofia Pusztai)

Experts from the WHO mission study groundwater maps with the local company responsible for water supply in the disaster area. The WHO mission to Hungary assessed the health risks in areas affected by the red mud spill. (Photo: WHO/Roger Aertgeerts)

The Head of the WHO Country Office, Hungary shows the disaster area on a map to members of the WHO mission. The mission was sent to Hungary to assess the health risks in areas affected by the red mud spill. (Photo: WHO/Roger Aertgeerts)

WHO sent a mission to Hungary to assess the risks to health in areas affected by the red mud spill, and advise the Government. The team provided international expertise in evaluating and managing risks to public health from the environment, particularly those related to water, sanitation and chemicals. The mission worked with the WHO Country Office, Hungary and Hungarian experts and authorities. (Photo: WHO/Zsofia Pusztai)

Workers spread gypsum on the soil in one of the Hungarian villages affected by the red mud spill. Gypsum reduces the corrosive effect of the mud. (Photo: WHO/Roger Aertgeerts)

Inside a house in Kolontar, Hungary, the closest village to the alumina plant reservoir that burst on 4 October 2010, pouring about 1 million m3 red mud into nearby villages. People from Kolontar were evacuated. Before the evacuated population can return home, extensive remediation and clean-up are needed, coupled with an assessment of risk exposure (e.g. to polluted air), particularly for vulnerable individuals. (Photo: WHO/Roger Aertgeerts)

A house in Kolontar, Hungary, the closest village to the alumina plant reservoir that burst on 4 October 2010, pouring about 1 million m3 red mud into nearby villages. Immediate health effects are associated with drowning and chemical burns. The burns are due to the elevated pH (>12) of the red mud, which has a corrosive effect on the skin and eyes. As the sludge recedes and its pH decreases, the potential for direct health damage from contact diminishes substantially. (Photo: WHO/Zsofia Pusztai)

Workers gather data on sediment dust quality in the disaster area. (Photo: WHO/Roger Aertgeerts)