Some environmental statistics only apply to BP whereas other figures take the whole of the site into account, such as the figures below, concerning the discharge through waste water.
These are the relative figures, expressed in kilogramme emissions per tonne end product.
The term 'other substances' includes metals, some BP production by-products, suspended solids as well as nitrogen and phosphorus.
COD is the abbreviation of 'Chemical Oxygen Demand'. With COD indicated substances require a certain amount of oxygen to decompose the 'pollution' in the water. COD reflects a kind of basic quality.