A holistic approach to risk monitoring for acute environmental spill to sea from all petroleum activities on the Norwegian Continental Shelf has been developed. The approach yields risk indicators based on reported discharges, as well as indicators based on precursor events which may result in spills if several barriers fail. Well kicks that have reservoir blowout potential have the highest indicator value. The second largest value is other hydrocarbon releases which may lead to secondary blowouts, riser/pipeline failure or structural damage and hence release of stored oil. External events that may cause structural damage to the extent that stored oil is released or secondary blowouts, is also a significant category. The suitability of the method is dicussed thoroughly.