 When road tankers unload liquid benzene or BTX into the respective tanks, vapour rich in these materials is discharged from the tank vent and is trapped in activated carbon beds.Benzene and BTX are purchased overseas and is transported to nearby Coode Island where it is unloaded from ships and stored in a similar tank farm before being transported by road to the West Footscray site.The tank farm also contains similar tanks that contain the finished product styrene monomer and various intermediate liquids.