The International Association of Oil and Gas Producers (IOGP) has collected and published environmental data from its Member Companies every year since 2001. The ultimate aim of this effort is to provide a representative statement on the environmental performance of the contributing IOGP Member Companies. Subsidiary objectives are to provide a basis for individual member companies to compare their environmental performance, thereby helping them to identify areas for improvement and to demonstrate the industry's wish for greater transparency concerning its activities. Environmental information is collected under the following categories: gaseous emissions energy consumption flaring produced water non-aqueous drilling fluids retained on cuttings discharged to sea spills fresh water Data are collected annually for each of the categories above, on the basis of a set of definitions agreed by the IOGP Membership. These definitions align with IPIECA/API/IOGP Report 437 - Oil and gas industry guidance on voluntary sustainability reporting. The definitions are provided via a user guide that is reviewed at regular intervals and updated to reflect improvements in reporting and to provide additional clarification.