The aim of this paper is to investigate how environmental policies, in the
form of emission charges or emission limits, affect the production-inventor
y decisions of a firm. Our framework applies control theory to analyze opti
mal production policies. The paper modifies the results of Wirl (European J
ournal of Operational Research 55 (1991) 191) to the case of concave produc
tion costs. (C) 2001 Elsevier Science B.V. All rights reserved.