File photo: Nuclear Regulation Authority (NRA) Secretary General Shunichi Tanaka (R, w/white helmet) inspects the radioactive water-leaked plumbing with Tokyo Electric Power Co. (TEPCO) officials at the Fukushima Dai-Ichi nuclear power plant in Okuma in Fukushima prefecture, on April 13, 2013.
Japan's nuclear watchdog is considering raising the danger level at the Fukushima plant to "serious." That's after 300 tons of contaminated water leaked from a holding tank there — some of it possibly reaching the Pacific.
Kei Iwamoto, a radiation researcher with UCLA, says the pollution may pose a threat to the immediate area — but beachgoers in California shouldn't worry.
"The ocean is so large and we are so far away. You know that 300 tons is equivalent to a drop in 50,000 Olympic-sized pools. So it's a huge dilution. And what we're going to see over here is going to be undetectable."
Officials with the nuclear plant are still hunting the source of the leaks.