An evaluation approach using the mathematical method of the Hasse diagram technique is applied on 20 environmental and chemical Internet resources. The data for this evaluation procedure are taken out of a metadatabase called DAIN (Metadatabase of Internet Resources for Environmental Chemicals) which is set up by the GSF Research Centre for Environment and Health and the University of Kassel. The following are chosen as evaluation criteria: search possibilities in Internet resources; quality of resources; number of chemicals in the resource; identification parameters for chemical substances; and information parameters for chemical substances. The 20 Internet resources are ranked with these five different evaluation criteria using a six-figure scoring system. A Hasse diagram is set up and discussed. A further analysis shows that the criterion "information parameters for environmental chemicals" is the most important one in this ranking procedure. (Contains 14 references.) (Author)