UltraClean (IMAGE) DOE/Oak Ridge National Laboratory Caption ORNL's Ultraclean Condensing Gas Furnace, which utilizes monolithic acidic gas reduction, or AGR, as the catalyst to remove more than 99.9% of acidic gases and other emissions, such as carbon monoxide, hydrocarbons and methane, from furnaces. Credit ORNL, U.S. Dept. of Energy Usage Restrictions None License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.