Purpose: The paper aims to address regulator-management interactions in environmental policy with reference to direct regulations, social regulations and market-based regulation. Design/methodology/approach: Revision of literature to identify the European Union regulations for companies producing polymers. Expert groups consultation to enrich the information and testing of the expert system (software). Findings: Interactions between actors dealing with environmental policy from government and business sectors cause high and growing transaction costs; in The Netherlands during 1990-2007, they represented an increase from 17 to 21 percent of all environment protection costs. Rapid, 14 percent average annual growth followed the shift from the direct to social regulations in the 1990s. Instead of the shift, better interactions management could have saved nearly four billion euro a year in the EU. In support of this, a web-based expert system is developed in a consortium of small and medium size enterprises and expert centers from seven European countries. Originality/value: The system, Environmentor, contains checklists with exemplary inputs, outputs, environmental standards and technologies for permits, process for implementation of environmental management systems, as well as an administrative model and auction for the EU emission trading.