Cerro al Lambro

At Cascina Gazzera, on the right bank of the Lambro south of Milan, two large floodplain areas were used as illegal dumps. From the 1950s about 100,000 tonnes of toxic and hazardous waste were tipped there, mostly acid sludge. The ministry's 2001 site sheet describes two areas, 'Danelli' (16,000 m²) and 'Montana' (about 35,000 m²), where acid sludge from the re-refining of waste oil and spent bleaching earths were illegally tipped: highly acidic sludge giving off sulphur-bearing gas, bituminous crusts, and a mass of sludge lying in the Lambro itself. According to the designers the main pit measured about 15,000 m², more than 4 metres thick. The first lot of works, worth about 56 billion lire, started on 12 December 2000.

On 11 November 1999 the Lombardy Region proposed to the Ministry of the Environment that the area be included among the remediation sites of national interest. Ministerial decree 468 of 18 September 2001 listed it and the provisional perimeter was set by decree of 8 July 2002. By decree of 11 January 2013 the site left the list of SINs and responsibility passed to the Lombardy Region.

According to the municipality, the ministry and the Region spent about 60 million euros over twenty years. By July 2024 the main area had been cleaned up; four further contaminated areas had come to light during the works, two of them already remediated.