Causes and effects of acid deposition are the subject of widespread discussion both in the U.S. and Europe. Two major concerns are the acidification of lakes and streams, and forest damage. The proposed mechanism for acidification of lakes and streams is the deposition of acidic materials such as sulfate and nitrate. While forest damage mechanisms must be established, one current theory is that it is the result of oxidants formed in the atmosphere by reaction of nitrogen oxides (NOx) and hydrocarbons. These acidic materials are postulated to be formed in the atmosphere from precursors, principally sulfur dioxide (SO2). NOx, and hydrocarbons, emitted from automotive, industrial, and utility sources. Conventional methods for reducing SO2 emissions from coal-fired power plants include flue gas desulfurization, coal cleaning, and switching to lower sulfur fuel. Several emerging technologies may provide more cost effective control of SO2 and/or NOx. The EPA is actively developing two such technologies: Limestone Injection Multistage Burners (LIMB) and E-SOX. The paper summarizes the status of the technology and discusses planned research and development activities.