Italy's nuclear physics research authorities have temporarily shut down an underground laboratory in a bid to resolve environmental questions that surround its work.

Almost all research at the Gran Sasso National Laboratory, an underground neutrino lab in central Italy, was halted by the Italian National Institute for Research in Nuclear and Subnuclear Physics (INFN) on 29 May.

The move follows warnings from local officials that toxic chemicals used in the lab could pollute local water supplies. Enzo Iarocci, the INFN president, says the closure is intended to draw attention to the problem, which he believes the national government must solve.

The lab has attracted protests since experiments began a decade ago. Environmental groups argue that the toxic chemicals used in the neutrino detectors could leak into aquifers below the lab. Their protests gathered pace last August, when around 50 litres of trimethylbenzene, a chemical that is toxic in high doses, were spilt during work on the Borexino experiment, which studies low-energy solar neutrinos.

The chemical entered the lab's drainage system, and local environmental officials subsequently detected it in a nearby river, although it was not found in drinking water. The local public prosecutor opened an inquiry into safety procedures at the lab, and the regional government set up a parallel expert inquiry staffed by water engineers, public-health officials and INFN representatives.

After assessing contamination risks, the prosecutor ruled on 29 May that the Borexino experiment area should be sealed up. Iarocci, having been told earlier that week by the expert group that the lab's drainage system could be leaking, the same day suspended all experiments involving liquid materials.

Iarocci says the repairs needed are the national government's responsibility. ”The INFN is also trying to give a sign of cooperation to local communities,“ adds Carlo Gustavino, a Gran Sasso physicist.

Alessandro Bettini, the lab's director, says the national government has reacted positively to the INFN's action, and that work at the lab could restart in around four months, as the repairs needed to the drainage system are minor.

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