As public concern grows about radiation from Japan possibly drifting to the West Coast of the United States, the U.S. Environmental Protection Agency on Tuesday announced that it will deploy more electronic monitors that measure radiation levels in the air.

The monitors, which detect gamma radiation and radioactive particles, will be set up in “parts of the Western U.S. and U.S. territories,” the agency said in a statement.

EPA officials, however, refused to answer questions or make staff members available to explain the exact location and number of monitors, or the levels of radiation, if any, being recorded at existing monitors in California. Margot Perez-Sullivan, a spokeswoman at the EPA’s regional headquarters in San Francisco, said the agency’s written statement would stand on its own.

Critics said the public needs more information.

“It’s disappointing,” said Bill Magavern, director of Sierra Club California. “I have a strong suspicion that EPA is being silenced by those in the federal government who don’t want anything to stand in the way of a nuclear power expansion in this country, heavily subsidized by taxpayer money.”

The EPA has 124 air monitors, which provide hourly readings, already in place in its “Rad-Net” system to measure radiation, including 12 in California and two in Hawaii. One is \in San Francisco, on the roof of the Bay Area Air Quality Management District.

Others are in San Jose, Sacramento, Fresno, Los Angeles and San Diego.

The EPA also has 40 mobile monitors, some of which are now being deployed. The agency clarified that some would go to Guam, Hawaii and Alaska, but did not respond to questions about California.

“As the Nuclear Regulatory Commission has said, we do not expect to see radiation at harmful levels reaching the U.S. from damaged Japanese nuclear power plants,” the EPA statement said.

Experts on Monday told the Mercury News that high levels of radiation are unlikely to hit California because Japan is 5,000 miles away. However, studies from the California Air Resources Board have found that coal dust and other pollution from China regularly reaches the state.

Most experts said that if the Japanese reactors experience a complete Chernobyl-type explosion, fire and release of nuclear material, some could reach California, but probably in very low amounts.

Meanwhile, another branch of the Obama administration generated confusion Tuesday. During a Northern California visit, U.S. Surgeon General Regina Benjamin was asked by a TV reporter whether California residents who are stocking up on potassium iodide are being extreme.

Potassium iodide blocks the thyroid from absorbing radioactive material. It is often used by people who are exposed to radiation.

“It’s a precaution,” she said. “You mean stocking up here? I haven’t heard that. But it’s a precaution, yeah.”

Benjamin toured Mills-Peninsula Medical Center in Burlingame and San Mateo Medical Center to discuss trends in electronic medical records and minority health.

State and county health officials in California have told residents not to take potassium iodide because the Nuclear Regulatory Commission has said that U.S. residents are not at risk from the disaster, and some people are allergic to the medicine.

After the surgeon general’s remarks were highlighted by the Drudge Report, a website that receives 36 million hits a day, with the headline “Surgeon General: Get Iodide,” the Mercury News asked for clarification.

“She commented that it is always important to be prepared; however, she wouldn’t recommend that anyone go out and purchase it for themselves at this time,” said Dori Salcido, a spokeswoman for Benjamin.

Cities across the West reported runs on potassium iodide at stores. Some websites selling Geiger counters also said they had sold out.

“I called six stores today in Santa Clara County,” said Charlie Bullock of Los Gatos. “You can’t find it anywhere. Hopefully, if any radiation gets over the ocean, it will disperse. But if it doesn’t, I’m afraid people in California will be caught off-guard.”

Contact Paul Rogers at 408-920-5045.