The contracts concluded with the two civil engineering consortia imposed environmental restrictions and, notably, the hiring of experts to perform environmental monitoring on the worksite.
- Noise
The noise generated by the work was limited to respect French and Swiss regulations. An acoustic system monitored noise levels at various times. Measures were taken to limit noise, such as the construction of a temporary building with noise barriers above each shaft to minimise noise pollution from the excavation, or the installation of mufflers on the ventilation systems for the underground work.
- Light pollution
To limit light pollution at Point 5, it was decided to limit during the nights the worksite lighting to the minimum compatible with the safety of the workers.
- Air
Host State regulations govern the release of dust into the air while the work is taking place. Measures were implemented, such as a wheel-washing system for lorries leaving the sites, vehicle speed restrictions and a sprinkler system in dry weather.
- Water
A worksite water management plan was established to prevent pollution. The excavation areas were protected from rainwater, as far as possible. A water treatment plant was installed on each site to treat all water coming from the worksite before it was discharged. The water quality was monitored.