Emission trading systems have been proposed in different regions to reduce polluting emissions and are in use in the European Union for carbon dioxide emissions. One of the objectives of these systems is to encourage firms to adopt advanced abatement technologies. However, permits also create an incentive to reduce output, which may be seen as negative by policy makers. We analyze the impact of a rigid labour market on these two outcomes, showing the conditions necessary to avoid reductions in production while keeping the incentives to improve abatement technologies. The analysis is done for oligopolistic firms engaged in international rivalry. (C) 2012 Elsevier Ltd. All rights reserved.