The U.S. Environmental Protection Agency does not plan to set a drinking-water standard for perchlorate, a common regional contaminant used in explosives like rocket fuel and fireworks.

The decision, first reported by The Washington Post, came in a document indicating the EPA had made a "preliminary regulatory determination" not to set a standard.

The Sun has obtained a summary of the report from staff for the Senate Environment and Public Works Committee.

According to the summary, the EPA draft underwent heavy editing from the White House, and the EPA's original suggestion to have a 45-day comment period was reduced to 30 days.

Perchlorate has been found at 400 sites nationwide, including more than 100 in California.

Locally, it has been found in especially high concentrations around Riverside, the San Gabriel Valley, Redlands and Rialto, where the EPA is close to naming a 160-acre area a Superfund site.

Perchlorate can interfere with the thyroid gland, affecting metabolism as well as mental and physical development.

California has set a maximum standard of 6 parts per billion, and Massachusetts has set one at 2 ppb in drinking water.

In 2002, EPA scientists developed a draft protective level of 1 ppb for drinking water, assuming all perchlorate intake comes from water. In reality, perchlorate is also found in milk, breast milk, lettuce and other food sources.

The National Academy of Sciences

was then tasked with coming up with a recommendation and came up with a reference dose of about 20 ppb, assuming a body weight of 150 pounds and that all perchlorate is ingested through water.

Environmentalists and some members of Congress blasted the news as an example of the White House and Pentagon - much of the perchlorate contamination is at old Pentagon and defense contractor sites - influencing the EPA.

"The Defense Department's response to perchlorate contamination raises serious questions about the appropriateness of its role in the EPA's internal regulatory process," Rep. Hilda Solis, an El Monte Democrat, and Rep. Gene Green, a Texas Democrat wrote to EPA Administrator Stephen Johnson.

The Sept. 23 letter asks for all communications on the issue since last year.

EPA spokeswoman Enesta Jones said the agency plans to issue the preliminary determination in the next couple of weeks and the final one by the end of the year but that "no decision has been made."

"This is an open and transparent process," she said.

Solis and Sen. Barbara Boxer, D-Calif., have sponsored legislation to require the EPA to set a perchlorate standard.

In March, the Government Accountability Office criticized the EPA's risk assessment process and said it is not transparent enough and allows too much influence from other federal agencies, including the White House.

Boxer mentioned the issue at a May committee hearing.

"We had a full hearing on a GAO report ... and the fact that EPA is trying to shunt the scientists to the back, put the (Department of Defense) contractors to the front - at the table - and they said it's very dangerous," she said at the May hearing.

An EPA decision not to regulate perchlorate in drinking water would not have a major effect on Superfund sites with perchlorate, like the one on its way to Rialto, said Kevin Mayer, the EPA's regional perchlorate manager and a Superfund project manager.

Treatment systems the EPA uses in Rialto should remove all perchlorate from the water, he said, but the agency won't have to clean water contaminated at lower levels than the state standard, 6 ppb.

"In a Superfund program, we're required to meet federal and state standards, and we're required to assess the risks for those contaminants that don't have standards," he said.