Work in difficult conditions resulting from limited visibility in conjunction with restricted movement and complexity of performed operations involves high risk. The hazard can be reduced significantly through rapid provision of information on the risks people are exposed to under certain working conditions. Their reactions - classified as improper - result most often under stress, in particular when acting in limited visibility conditions. This article shall treat of reduced visibility understood as lack of visibility resulting from dim light, as opposed to the problem of obstructed view, which is not discussed here.