Japanese authorities failed to disclose U.S. data about the spread of radiation from a crippled nuclear plant last year, leaving some evacuees fleeing in the same direction as the emissions, according to several media sources.

News that Japan's nuclear watchdog and the science and technology ministry sat on the information collected by U.S. military aircraft -- another sign of the chaos at the time - is likely to add to mistrust of nuclear power just days after the government approved the restart of two idled reactors.

Japanese Industry Minister Yukio Edano apologized Tuesday for the nation's failure to make use of the data, according to the Asahi Shimbun newspaper.

"It is extremely regrettable that [the information] was not used by the government," Edano was quoted as saying. "I apologize to the people who were affected."

On March 11, 2011, an earthquake and tsunami devastated the Fukushima nuclear plant north of Tokyo, triggering explosions and meltdowns and causing about 160,000 people to flee the worst nuclear accident since Chernobyl in 1986.

U.S. aircraft - reports differed on whether they were operated by the military or Department of Energy - gathered radiation data from March 17-19 within a 28-mile radius and found that people in an area about 15 miles northwest of the plant were exposed to the annual permissible level of radiation within eight hours, Japanese media said.

A registry created by the Pentagon to gauge U.S. citizens exposure to radiation is set to go online in July after months of delays.

U.S. troops wore dosimeters during relief efforts around the disaster zone, and the U.S. took soil and air samples, though no data has been released, despite repeated requests.

The information was passed to Japan's Nuclear and Industrial Safety Agency and the science and technology ministry by Japan's Foreign Ministry, but neither agency passed it to the prime minister's office, which was overseeing the evacuations.

The government had admitted that it failed to quickly disclose computer forecasts showing the direction that radioactive material would disseminate, due to poor internal communication.

In the absence of warnings, thousands fled in the same direction as the drifting radioactive material, Reuters news service noted.

Edano declined to comment on whether any government officials would be fired or otherwise punished after the panels' reports are issued.

Japan will also set up a new nuclear regulator in a few months after the expected passage of an enabling law, part of efforts to repair shattered trust in a regulatory regime long characterized by cozy ties between bureaucrats and utilities.

Although no one is officially recorded as having died as a direct result of the radiation, it forced tens of thousands of people from their homes, with many still unable to return, Agence France Presse reported.

Scientists say contamination has made some areas around the plant unfit for farming and fishing for many decades to come, AFP added.

All of Japan's 50 reactors have gone off line for safety checks and maintenance since the disaster, Reuters said.

Despite public opposition, the government on Saturday approved the resumption of operations at two plants in western Japan to avert a power crunch.

Sign Up for Daily Headlines

Sign up to receive a daily email of today's top military news stories from Stars and Stripes and top news outlets from around the world.

Sign Up Now