Trento Nord (former SLOI and Carbochimica works)

The Società Lavorazioni Organiche Inorganiche (SLOI) moved to Trento in 1939 and made tetraethyl lead from 1941 to 1978. Working conditions were very bad: in the 1960s, 325 acute lead poisonings were reported and over a hundred workers were admitted to hospital with neurological disorders. Next to SLOI (about 5.5 hectares) stood Carbochimica Italiana, formerly Prada (about 5 hectares), the second plant inside the perimeter: active from the early 1900s to the early 1980s, it distilled tar and made naphthalene, wood-treatment oils, pitch, phthalic anhydride and fumaric acid.

On the evening of 14 July 1978, during a storm, water got into the sodium store: the drums caught fire and exploded, raising a toxic cloud. About thirty people were taken to hospital. The fire brigade smothered the fire with cement. Three days later the mayor ordered the plant closed and the prosecutor seized it.

Organic lead soaked through the ground down to the Adige aquifer and reached the ditches that cross the city. Groundwater taken from the site held on average 95 µg/L of total organic lead, nearly all of it triethyl lead. According to SENTIERI, mercury is also present in the site's environmental media. The ministry's 2001 site sheet attributes the mercury to SLOI's chlor-alkali unit. On the Carbochimica area the typical pollutants are PAHs, aromatic solvents and phenols, with a plume of naphthalene, aromatic solvents and phenols in groundwater; the sludge and bed of the Lavisotto stream and the other ditches are also polluted to a depth of several metres. The same sheet notes that in groundwater phenols, aromatic solvents and naphthalene decline with distance partly through natural biodegradation, as do the breakdown products of tetraethyl lead, while three- and four-ring PAHs show no evident biodegradation.

The site has been a SIN since 2001. The first phase of the clean-up, covering the ditches, was funded in 2007 with 27.5 million euros and the first lot was contracted in 2020. There is no timetable for the soil: no proven technology exists for organic lead and containment is being discussed.