This paper aims to clarify applications of human factors science in the offshore process industry in terms of what can be done, why and how. Illustrative examples are given. An explanation is given of the meaning of ＇human factors＇, and the use of human factors science before and after the Piper Alpha disaster is outlined. The influence of approaches developed after the nuclear Three Mile Island accident is discussed briefly. The need for human factors review of offshore installations in design, construction and operation is highlighted by providing quantitative information on underlying causes of loss-of-containment accidents. Human factors review should be part of the safety management system, which is described in terms of a set of control and monitoring loops; the control and monitoring requirements for optimizing human performance are outlined briefly. Using the concept design stage of an installation as an example, the use of human factors review in safety decision-making is exemplified by indicating which areas should be targeted for review and how this would influence safety. Key human factors review methods are identified and an example is given of one approach, a ＇walk-through＇ of design and procedures. It is concluded that identification of causes of accidents has prompted the development of human factor applications, but that there is still room for much more comprehensive and long-term human factors programmes in the offshore industry, with considerable potential for risk reduction.