Californian authorities on Tuesday ruled out the possibility that radiation from Japan would pose a threat to the U.S. West Coast.

"There is no danger at this time," Jordan Scott, a spokesman for the California Emergency Management Agency said, citing assurance from nuclear experts.

The West Coast is 5,000 miles (8,000 kilometers) away from Japan and such a long distance would keep harmful radiation away, experts said.

"Things would have to get kind of 'end of days' for us to see even a little bit of it here. We're talking very extreme," Scott said. "We're just too far for anything to really reach us. A majority of the materials that would come out of there in a meltdown would dissipate" within miles, Scott said.

He said experts assured his agency that should a meltdown occur at one of Japan's quake-damaged nuclear reactors, "it is highly unlikely that we would see any effects of it here."

"That being said," Scott said, "we are doing our due diligence in monitoring the situation and making sure we have the most updated information."

Scott said Californian residents should not just focus on preparing for a potential nuclear disaster but on preparing for any of the natural disasters that routinely strike the state, including floods, wildfires and earthquakes.

"It's a big reminder to people that we are vulnerable to all sorts of disasters," Scott said, "and we need to get prepared."

The California Department of Public Health spokesman Mike Sicilia said state health officials kept close watch on potential radioactive releases at Japanese nuclear plants, making conference calls to local and federal officials every few hours.

"The Department of Public Health has radioactive monitoring for the water, food and the air," Sicilia said. "We do have a plan of response and constant contact with our partners. From a health standpoint, we're not concerned at this point."

Earlier, the Nuclear Regulatory Commission said small releases of radiation from Japan's crippled Fukishima reactors were a threat to the U.S.

Available information indicates that weather conditions have carried any radioactive vapors out to sea and away from the Japanese population. Given the thousands of miles between the two countries, Hawaii, Alaska, the U.S. territories and the U.S. West Coast are not expected to experience any harmful levels of radioactivity, the commission said.

The Union of Concerned Scientists, a group that has been critical of nuclear energy, said it was also watching the Japanese crisis unfolding.