PARIS (AP) — French authorities say a rock slide has killed one technician and injured another at a vast underground site slated to become a major repository of highly radioactive nuclear waste.

A rock face at an underground laboratory in northeast France collapsed Tuesday while the technicians were conducting tests, according to the regional French administration and Andra, the state radioactive waste management agency.

The regional administration said the laboratory at the site in Bure was evacuated and emergency workers and labor inspectors sent to the site. An investigation is underway by the regional prosecutor.

France is heavily dependent on nuclear energy. The country has been working for years to test the rock and prepare the site at Bure to hold radioactive waste. The Bure site does not hold any radioactive waste itself, but is a research and experimentation lab to help prepare the future site, Andra said in a statement.