Overturning a 2008 decision by the Bush administration, the Environmental Protection Agency announced Wednesday that it will establish a federal limit on the amount of perchlorate in drinking water. This would be the first nation-wide limit and would crack down on the naturally occurring and artificially produced chemical that is used in rocket fuel, fireworks, flares and missiles. The reason for concern is that the EPA says perchlorate may have an impact on the thyroid, which Time Magazine's Bryan Walsh calls a "nasty" chemical because it hinders the "thyroid's ability to produce hormones needed for developing fetuses and infants."

According to an EPA study, the chemical's reach is not small: "more than 4 percent of public water systems have detected perchlorate and between 5 million and 17 million people may be served drinking water containing perchlorate." Furthermore, The Washington Post's Brian Vastag notes that the FDA peeked into just how pervasive perchlorate was in the food supply in 2006 and found it in 74 percent of the items it tested. Unsurprisingly, Wednesday's announcement has its critics. Among them: The Perchlorate Information Bureau, whose spokesman Bill Romanelli thinks this is about ideology. The Perchlorate Information Bureau, of course, "is supported by Aerojet, American Pacific Corporation and Lockheed Martin," so Romanelli might not be the most impartial observer, either.

At present, the EPA is still hammering out what the limit should be, when it will roll out, and just how much it will cost to implement. Despite these open ended issues, however, commenters saw no reason to hold back their praise, their critcisim or their questions.

• Why Is This Taking So Long? asks the National Resources Defense Council's Jennifer Sass. Although Sass is excited that the EPA is going after perchlorate, she told the Washington Post that we shouldn't be waiting for more information to move forward. "Anything that anybody needed to say about this process is already done," she says. On her blog, Sass also notes that "after more than 17 years of accumulated science on perchlorate harms, two EPA toxicological reviews (1998, 2002), and a lengthy review by the National Academies (2004), it is past time for EPA to take effective regulatory action to protect people’s health by preventing exposure to perchlorate."

• This Reverses a Huge Mistake  The Washington Post's Brian Vastag says that the Bush Administration had an opportunity to clean up our drinking water but went out of its way not to, noting "a Washington Post investigation at the time found that officials from the Bush administration heavily edited a key EPA report to play down the risks of the chemical. A Government Accountability Office report also found that the Defense Department--which, along with NASA, is a heavy user of perchlorate--sought to derail any perchlorate standards."

• Score!  The National Resources Defense Council's Mae Wu says the EPA's Lisa Jackson is proof that things are moving in the right direction. She says "given the science on the impact of perchlorate on normal thyroid function and the data on the widespread occurrence of perchlorate throughout the U.S., this determination marks the Agency finally coming to its senses."

• It's Unnecessary  The Perchlorate Information Bureau says the EPA is wasting everyone's time and the should back off because "despite 50 years of scientific research that indicate the low levels of perchlorate being detected in the environment have no effect on human health." Further, the industry group notes that several states--such as California--already have limits in place, so the EPA's declaration is unnecessary: "much is already being done--even in the absence of a regulatory standard--to further ensure public health is protected."

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