WASHINGTON— The Environmental Protection Agency announced Wednesday that it will set a national drinking water standard for the toxic substance perchlorate. The EPA said it was reversing a 2008 Bush administration ruling.

EPA Administrator Lisa Jackson made the announcement before she testified at a Senate Environment and Public Works Committee hearing.

The meeting focused on the EPA using the “best available science” to continue to evolve and update safe drinking water standards. The EPA has not yet finalized the rules.

“We need to keep pace with increasing knowledge and potential public health implications from the growing number of chemicals that may be present in our products, our water, and our bodies,” said Jackson.

Perchlorate, the now-regulated chemical, contaminates water supplies in at least 35 states and has already affected between 5 and 17 million Americans. Perchlorate is both a naturally occurring and man-made chemical. It can be found in fireworks, road flares, rocket fuel and may exist in bleach and some fertilizers. Perchlorate can disrupt the thyroid and have a dangerous impact on the development of fetuses and infants, making it a vitally important chemical to control.

“I could not emphasize enough the importance of using the best science, sound science … the issue here is the extra layer of protectedness for pregnant mothers,” Jackson said.

The overall reaction to the announcement was positive. Many members thanked Jackson after her testimony.

“I just have to say you make me very proud,” said Sen. Barbara Boxer, D-Calif., chairwoman of the Environment and Public Works Committee. In a written statement she added, “I will do everything I can to make sure this protection moves forward.”

The committee also discussed a toxic form of chromium called chromium-6. Science has already proven that inhaling chromium-6 causes cancer and EPA scientists are now studying the dangers of drinking this chemical and how prevalent this contaminant is in our drinking water. To help determine the prevalence of chromium-6, the EPA has released guidance on how to sample and test drinking water.

The EPA will continue testing on chromium-6 throughout the year to ensure sound and complete scientific investigation and knowledge before moving forward on any regulations.

“Strong science and the law will continue to be the foundation of our decision-making at EPA,” said Jackson.

Jackson also outlined a four-step drinking water strategy. Highlights from that strategy include the announcement that the EPA will now work with contaminants in groups, as opposed to individually, to allow for quicker and more efficient regulation. Volatile Organic Compounds, which cause cancer, make up the first group the EPA is evaluating. Another component of the drinking water strategy is to develop new drinking water technologies, which Jackson said she hopes will encourage economic growth and create jobs.

As far as receiving money to finance the new reforms, Jackson made her case that it won’t cost that much: “We can be protected for a reasonable amount of money to ensure that are children to not get sick,” she said.