The aim of the present paper is to provide a metalogical systematisation in the area of deontic action logic based on Boolean algebra. Differences among the systems in question lie in two aspects: the level of closedness of a deontic action logic and the possibility of performing no action at all. It is also shown that the existing definitions of obligation in those systems are not acceptable due to their unintuitive interpretation or paradoxical consequences. As a solution we propose an axiomatic characterisation of obligation with an adequate class of models. Key words: deontic action logic, obligation, Boolean algebra