This study investigates the causality from environmental investment (as a long-term effort) and expenditure (as a short-term effort) to financial performance in the US electric utility industry. The industry is one of the large air polluters in the United States. This empirical study finds that the environmental expenditure under the US Clean Air Act has had a negative impact from 1989 to 2001. The negative impact has become much effective after the implementation of the Title IV Program (1995) of the US Clean Air Act. This study cannot find the influence of environmental investment on financial performance by a statistical test although it indicates a positive impact. In the United States, fossil-fueled power plants such as coal-fired ones still produce a large portion of electricity. The generation structure is inconsistent with the betterment in the US environmental protection and imposes a financial burden to electric utility firms. (C) 2009 Elsevier Ltd. All rights reserved.