Introduction

The evolvement of the idea of transboundary environmental impact assessment (hereafter transboundary EIA or TEIA) is connected with the development of EIA in general, because a TEIA procedure is simply a means of extending the national procedure to foreign impacts and foreign actors. The first national EIA procedures appeared in the late 1960s and early 1970s, and they have since spread worldwide. However, the first TEIA procedure of international importance was the 1985 EIA Directive of the then European Community (EC). ¹ Hence from the beginning, the EC, eventually replaced by the European Union (EU), ² has played a key role in expanding EIA to transboundary impacts. Currently, most of the increasing TEIA practice takes place between Member States of the EU, or between Member States and non-Member States of the EU.