Document OEmDz5a8m2X1EyNwk7QmxknNw

American Water Works Association April 9, 2018 Mr. David Ross Assistant Administrator, Office of Water U.S. Environmental Protection Agency 1200 Pennsylvania Ave, NW Washington, DC 20460 Dear Assistant Administrator Ross, First and foremost, I congratulate you on your confirmation as Assistant Administator for the Office of Water. It is a wonderful organization with many talented and commited staff whose shared mission is the application of sound science to guidance policy decisions. In that regard, I would like to share our concerns with Agency's proceedings associated with perchlorate. Many of these concerns were expressed in a 2016 letter to Administrator McCarthy as the Agency was embarking on a third review effort following assessments by the National Academy of Science (2005) and EPA's Science Advisory Board (2013). The Agency's current draft approach has not allayed our concerns. Our review supports the conclusions of prior studies that low levels of perchlorate have no demonstrated health consequence that can be scientifically validated with the confidence necessary to support regulatory action. While we support the modeling efforts applied by the Agency, the perchlorate model is not fit for purpose and, if accepted, would set a troubling precendent for the scientific integrity of the Agency's regulatory process. AWWA appreciates the opportunity to share these concerns with you and share your commitment to ensuring that sound science guides the Agencies actions. If you have any questions, please feel to call Kevin Morley or me in our Washington Office at[____ Ex. 6____ ] Yours Sincerely, G. Tracy Meh Executive - Government Affiars Enclosure: Letter to Administrator McCarthy, April 5, 2016 CC: Lee Forsgren, OW Peter Grevatt, OGWDW Deborah Nagle, OST Sierra Club v. EPA 18cv3472 NDCA Tier 5 ED 002061 00095868-00001