NAVAL AIR FACILITY ATSUGI, Japan – The military began distributing potassium iodide pills as a precaution against radiological sickness at bases on the Japanese main island of Honshu, but emphasized that no one should take the pills unless directed.

As of Monday afternoon, detected radiation remained no threat to public health, according to command officials.

“This decision is purely precautionary and while there is no indication of increased exposure, this decision reduces the health risks associated with potential exposure to certain forms of radiation,” according to a U.S. Pacific Command statement. “No one should take [potassium iodide] at this time. No one should take KI in the future unless advised to do so by U.S. or Japanese authorities.”

The potassium iodide pills were available for pickup on Navy bases at Yokosuka’s Purdy Gym, the Negishi movie theater, the Ikego gym and Atsugi’s Halsey Gym as of 12 p.m. Monday.

Both Yokota Air Base and Camp Zama were in the process of setting up distribution lines for the pills Monday afternoon with dissemination expected to begin within the next 24 hours, officials said.

“We’ve got plenty enough for everybody and everybody on this base,” Col. Fred Stone, deputy commander of the 374th Medical Group at Yokota, said during a radio address Monday afternoon.

During the broadcast, Stone and 374th Wing Commander Col. Otto Feather emphasized that distribution of the pills is only a precaution and is not mandatory for residents.

“The (radiation) levels are still pretty much inconsequential,” Feather said, adding that the air and water at and near Yokota is constantly monitored.

“I think we’re in good shape,” Feather said, noting all the reports he has receive from the “smart guys” in town from U.S. agencies.

Feather said the potassium iodide would be handed out at Yokota’s hangar 15 and advised listeners to tune into the command channel for more details. Those seeking the pills are asked to send one member per household to the distribution line.

Officials at Misawa Air Base said there is no current plan to distribute potassium iodide pills, even though they’re in stock at the 35th Medical Group.

“At this point and time, we are not distributing (the pills) because we are way outside of the affected area,” Air Force spokesman Tech. Sgt. Phillip Butterfield said Monday evening. “We don’t need to do it now.”

The order came out first through Commander Naval Forces Japan, but was quickly sent out as a Pacific Command directive.

Potassium iodide, known chemically as KI, blocks absorption of radioactive iodine, which is one of the chemicals released from the damaged Fukushima Dai-ichi nuclear power plant.

Japanese government officials said Monday that there are currently sufficient stockpiles of potassium iodide.

The government has been sending pills to residents living close to the power plant, said Masayoshi Shibatsuji, spokesman for the Ministry of Health, Labor and Welfare’s disaster headquarters.

“We have asked manufacturers for an increase in production to make sure no shortage occurs in the future,” Shibatsuji said. “However, at this point, there is no problem to meet the demand.”

Potassium iodide “works by blocking radioactive iodine from entering the thyroid,” according to the Centers for Disease Control website. “When a person takes KI, the stable iodine in the medicine gets absorbed by the thyroid. Because KI contains so much stable iodine, the thyroid gland becomes “full” and cannot absorb any more iodine — either stable or radioactive — for the next 24 hours.”

Appropriate dosages following radiation exposure may vary based on age and other factors, and should only be taken as directed by a doctor.

There is enough potassium iodide for all bases in Japan, according to Navy officials.

When asked why the distribution was beginning Monday, Cmdr. Ron Steiner, Commander Naval Forces Japan spokesman, said it wasn’t in response to any new radiation threats.

“This is to be extremely cautious,” Steiner said.

Atsugi residents picking up their pills Monday afternoon said that they were trying to remain calm.

Sarah Nestler, a military spouse, said she understood that handing out the pills was only a precaution. It made her a little nervous, but only because “it’s hard to know what's going on with so many different stories going around.”

“But I'm not freaking out about it,” she said. “I’m just trying to follow directions and do what they think is best for us.”

Bridget Sims, also a spouse, said she believed that this was just a case of the Navy erring on the side of safety.

“I do appreciate the concern,” Sims said.

Stars and Stripes reporters Grant Okubo, T.D. Flack and Charlie Reed contributed to this report.