There has been a strike at the Castagnola construction site after the collapse of the tunnel. A worker has been hospitalized in a serious condition with multiple fractures in his body. He is said to be not in life threatening condition. According to Italian news sites (Giornale7) there was a "crust of cement detached from the vault of the gallery". Workers decided to strike for 4 hours to pay attention to work safety. 

Safety of the site is being inspected by the authorities, where new possible collapses are feared. Friability of the rock in that stretch is a suspect for the collapse.

Castagnola is one of the many tunnels on the under-construction Tortona–Genoa high-speed railway, also known as Terzo Valico. It is for for high-speed, high-capacity railway linking Genoa to Tortona near Milan. When completed in 2023, it will be 53 kilometers long with 36 kilometers of tunnels. The railway is an important part of the Trans-European Transport Networks project (in its Rhine–Alpine corridor).

Castagnola tunnel is being built by Technoscavi, a subcontractor of the CGT consortium.