Court shuts dark matter lab

Europe's largest underground physics laboratory, housed in three chambers in the Gran Sasso mountains of central Italy, has been closed by a court order after complaints from environmentalists after a leakage into a river.

The Gran Sasso Laboratory specialises in research into neutrinos and "dark matter". It is the pride and joy of the Italian Institute of Nuclear Physics (INFN). The chambers are used by researchers from all over the world, including Stanford and Cambridge universities. Current ventures include a dark matter project involving researchers from Germany and Oxford.

A 1.4km layer of rock shields the chambers from almost all cosmic radiation, making them ideal for experiments that might be affected by radiation.

A Gran Sasso official said: "In August, a human error sent about 50 litres of pseudocumene (a petroleum derivative less polluting than petrol) draining into a local river. Immediately, Borexino - the experiment charting the fall of solar neutrinos - was shut down. Now the court has ordered the entire chamber to be sealed off."

In September, the INFN halted all experiments using liquid chemicals in the other two chambers. The court must decide if the safety systems of the laboratory are adequate, against the backdrop of long-standing tension with environmental groups.

"We care a great deal for the safety of those who live in the area," said INFN vice-president Angelo Scribano, "but we also care about our experiments. That's why we have decided to stop work until any doubts are cleared."