If you passed CERN’s Entrance A during the hours of darkness over the last few days, you might have noticed a flare as engineers burned off an underground pocket of gas.

During the drilling of the first geothermal borehole for Science Gateway next to CERN’s Entrance A, gas was detected at a depth of 200 metres. This is a relatively common occurrence at construction sites in the Geneva region, and the gas had to be burned off before work could continue. Drilling was suspended for three days and a flare installed by the contractor. The gas was completely consumed on Sunday 28 at 21:00h and the flare removed.

This article was amended on 2 March to signal the completion of the burn off.