In this paper we consider the use of border adjustments to compensate exporters for domestic environmental taxes even when the environmental tax is imposed on an intermediate good. Although GATT/WTO rules allow for border adjustments, there has been little analysis of them. A model of successive oligopoly is used to consider the appropriate border adjustments since many industries where environmental excise taxes are applied can be characterised as imperfectly competitive. We show that the border adjustment currently allowed for in GATT/WTO rules is, under certain circumstances, likely to be too low to maintain the competitiveness of exporters. In some cases, an export tax would be justified.