What are the stimulus properties that affect risk? Is it possible to assess the environmental risk of an industrial site by analysing the company's site or a photograph of the site? Often banks do this kind of inspection in case of a credit application or for new insurance contracts to judge environmentally caused credit risks. Both from the scientific and from the practical point of view it would be useful if a valid assessment of environmental risks of company sites done by visual perception could be done, including which environmental stimuli are affecting risk cognition in this field. To analyse this kind of perception of the manmade environment by visual stimuli, we tested the influence of the stimuli order, brightness, big structures, Gestalt, modernity, borders and newness in a quasi-experimental design with 54 participants, half of them bankers and half of them students. As control variables we used some personal and societal variables often linked to risk cognition. We presented 21 photographs of company sites to each participant for a fixed amount of time. Each participant had to judge the environmental risk of the sites. In addition, we assessed the perception of different stimuli and personality variables connected with risk perception. We found that bankers and students differ in their risk estimations and that stimulus characteristics were unstable, varying in their salience by site but not by persons. We identified objects and stimuli, which also increased or decreased environmental risk perception. Personality characteristics were inconsequential. The findings are usable for training measures for persons who have to judge environmental risks of sites. More research has to be done to identify stimuli affecting risk perception and cognition of manmade environments and to analyse the connection between stimuli and site characteristics.