NSF International recently added perchlorate to its list of chemicals that drinking water treatment units can be tested against. The new requirements, under NSF/ANSI Standard 58: Reverse Osmosis Drinking Water Treatment Systems, test and certify drinking water treatment units to ensure that products are available to reduce consumer exposure to perchlorate, a naturally occurring and manmade chemical used primarily in the United States as missile and rocket fuel. For an updated list of water treatment devices that comply with NSF's perchlorate reduction testing protocol, visitwww.nsf.org/certified/dwtu.