During the recent twenty years, the notion of ecological prevention has become a core Orientation for the environmental policies of both, the state and the management of big enterprises. Nowadays it is difficult to find an enterprise which would not claim preventive environmental protection to be a component part of its policy. This paper focusses an the environmental liability act and thereby discusses the relationship between state and private environmental protection. Considering environmental liability, the aspect of prevention, rather than the one of compensation, will direct the following discussion. It is assumed that ecological prevention depends an whether specific economic and cognitive pre-conditions are fulfilled. As soon as they are not fulfilled, environmental liability reveals striking weaknesses which can be observed in cases of accidental (sudden) damages as well as gradually developing damages. The former can be explained by a lack of economic conditions which is a consequence of the actually carried out risk-transfer to insurance companies. The latter are due to the lack of cognitive pre-conditions, i. e. the risks are simply unknown . Furthermore, the paper deals with the distinction between known, unknown and hypothetical risks, which is crucial for our discussion. Last not least, it outlines the problem of risks which arise as a consequence of risk-prevention- measures enacted by economic or political organizations.