The Pacific Ocean is Safe After the Fukushima reactor accident, radiation leaked into the Pacific Ocean, sparking global worry. In the months after the accident, levels were high, but not high enough to cause marine life die-off. For the last five years, all fish caught off Japan has been below the radiation thresholds for consumption. Radioactive cesium levels have been low since 2014, and levels of radiation off the California coast are lower today than they were in the 1960s when the US detonated hydrogen bombs in the Marshall Islands. Swimming in the Pacific for eight hours every day is less risky than one dental x-ray. Our Radioactive Ocean A crowdsourced science campaign called Our Radioactive Ocean was created to measure ocean radiation at various points in the Pacific. Interested citizens collected ocean samples and sent them to Woods Hole to be analyzed. The campaign became a hit, and more than 300 data points have been plotted up and down the West Coast. More than 1 million people have visited their site. Once citizen scientists got involved in the project, they wanted to learn more and engaged their communities. Communities, like Laguna Beach, began to band together to pay for samples. The data used is credible and has resulted in at least one scientific paper. Thanks to the public nature of the effort, new data points are continuing to be analyzed today. Radioactive World Radiation is a naturally occurring phenomenon, and we live with it every day. Even without human interference, the ocean still has radiation because of dissolved radioactive agents found in salt. Radiation in small doses is natural and perfectly healthy. Living at a high altitude exposes you to cosmic radiation and flying from New York to Japan gives you a dose of radiation much higher than background levels. Living in New England exposes you to elevated levels of radiation thanks to the large amounts of granite, which releases it. Many foods, like bananas, have trace amounts of radiation. Getting a dental x-ray or CAT Scan gives you a dose of radiation. We live with radiation and should not be afraid of it, except in extremely high doses. Find out more: Ken Buesseler is a marine radiochemist who studies the fate and distribution of radioactive elements in the ocean at the Woods Hole Oceanographic Institution. His lab has also been active in response to radioactivity released from disasters such as the impact of radioactivity released from the Fukushima Dai-ichi nuclear power plant, and from earlier sources such as Chernobyl or atomic weapons testing at the Marshall Islands. He created the Our Radioactive Ocean project, which uses citizen scientists to measure radiation levels on the West coast of United States. He also leads WHOI's Café Thorium, which analyzes marine samples for both natural and artificial radionuclides. You can follow him on Twitter @cafe_thorium.