fuel vapours emissions

Petrol contains volatile organic compounds (V.O.Cs) that evaporate in storage tanks.

During unloading of petrol to an underground storage tank or refueling of a vehicle, petrol vapour in the tank will be displaced by the incoming petrol.

The regulation is requiring the petrol station company to collect the underground storage tank vapors towards the truck that is delivering the fuel. (Phase 1)

Unless controlled, the petrol vapour will dissipate into the atmosphere.

The regulation is also requiring to collect the refueling vehicles vapors and to send them towards the underground storage tank. (Phase 2) 
Then those vapors will be collected by the truck during the next fuel unloading (Phase 1)