This study provides a cost-benefit analysis of the flue-gas desulfurization (FGD) systems installed at the Mae Moh power station in northern Thailand. A 'before and after' study focused on the impact this air pollution cleanup technology had on human health in the area surrounding the power plant. Impacts on local agricultural and forest productivity are also assessed. The setup and operational costs of the plant, along with other key costs, are compared with the economic value of all the benefits that the FGD systems will bring over their twenty-five year lifespan. The study finds that this cleanup technology has not been cost effective at this site - in other words it is an economic burden, rather than a benefit, to society. While the study acknowledges that the pollution clean up has had many positive benefits, it argues that cheaper options could have been considered.