Radiation From Fukushima Reaches US West Coast: What Danger Does Cesium-134 Pose?

A plume of radioactive material has been on a steady march across the Pacific Ocean since Japan's Fukushima nuclear disaster in 2011. And it just arrived on the United States' doorstep. The first traces of radiation from the leak have been detected about 100 miles off the coast of Eureka in northern California, researchers from the Woods Hole Oceanographic Institution in Massachusetts reported Monday.