Abstract The petroleum industry must satisfy energy demand while safeguarding the environment as global interest in sustainability rises and more zero discharge regimes emerge. Operational discharges from offshore vessels and structures cause untold damage to ecosystems but rarely make news headlines as these acts are mostly perpetuated in the open sea, at night and impacts are less visible due to advection. Oil spill response is complex, expensive and long-lasting. Chemical releases are more difficult to clean and the environment is seldom completely restored, making prevention more desirable. This paper was informed by this scenario and identified gaps in the literature, which mostly reports accidental spills. The nature, sources, causes and effects of operational discharges are highlighted; existing preventive and remediation measures are critically evaluated, and the imperatives of recent regulatory changes for process safety are examined. Live cases are cited from across the globe to assess typical solutions and/or penalties deployed. Relevant local, regional and international regulations are juxtaposed with developments in design, operating procedures and asset integrity measures for selected case studies. Since the ratification of MARPOL 73/78 by certain countries, subsequent decades have seen the continual operation of tankers without segregated ballast tanks, double hulls and other spill prevention design features at major oil loading and unloading hubs across the Gulf of Guinea. Several discharges go unreported and the penalties are barely enforced by regulators. Taking a cue from mature zero discharge regimes such as Norway, discharge prevention measures would be economically viable, address environmental considerations and enhance the corporate image of operators. In a comparative analysis of the value of energy production, social and environmental concerns often indicate great disparity. Creating a good balance on the economic scale will possibly show a different and more realistic perspective on the cost of production. This paper advocates a proactive and preventative, rather than the reactive and curative approach typical of most previous studies. Implementation of recommended engineering and administrative controls are hoped to aid the industry's drives towards zero harm, self-regulation and social license-to-operate in a world apprehensive about oil and gas. They will strengthen regulators in developing economies with heavy dependence on hydrocarbons and poor enforcement, where operators often overlook regulations.