Fashewar iskar gas masu ƙonewa, kamar methane, yawanci faruwa a cikin tunnels. Dokokin kula da aminci na gine-gine suna buƙatar amfani da na'urorin walƙiya masu hana fashewa.
Fashewar iskar gas masu ƙonewa, kamar methane, yawanci faruwa a cikin tunnels. Dokokin kula da aminci na gine-gine suna buƙatar amfani da na'urorin walƙiya masu hana fashewa.