 A decade ago, the accident at Tepco's Fukushima Daiichi Nuclear Power Station released radioactive material into the air and sea. According to Japan, the marine radioactivity levels have been steadily dropping since the accident. To ensure transparency, international scientists were invited to come and check in person. Such verification missions are held regularly, with publicly available results. The experts came to Fukushima to observe the Japanese scientists at work. Sea water, sediment and fish samples were jointly collected and analysed in Japanese and international laboratories. Our project supports transparency and the comparability of the data on international scale. An inter-laboratory comparison is a service offered by the International Atomic Energy Agency to its member states to double-check the reliability of their methods for monitoring the environment. This helps a country ensure the quality of its environmental data. It also provides reassurance locally and to the international community that they can have confidence in the results being reported. The team's first step is a boat ride to the waters just off Tepco's Fukushima Daiichi Nuclear Power Station. IAEA experts watch as a grab sampler is thrown overboard to collect sediment from the ocean floor, which is drained, weighed and bagged. Next water must be collected for multiple points around the power station. In the years after the accident, monitoring boats came out here monthly, at times with independent observers on board. After four hours' close observation at sea, it's time to go back to the harbour. A portion of the samples are packed for shipping directly to the IAEA and labs in different countries, while others are kept for analysis in Japan. To build a more complete picture of the marine radioactivity levels, the team also needs to collect freshly caught fish. The scientists select the fish that are most likely to reveal even low levels of radiation to be sent to the labs for analysis. Seafood from here is among the most tested in the world, with a sample from every catch checked for radiation. The IAEA has been regularly double-checking the data released by different Japanese agencies and has consistently produced matching results. Straight after the accident, the levels of radionuclides in the water off the plant were high, but they dropped back to almost nothing in the decade following as the waters dispersed. Marine radioactivity expert Paul McGinnity has been working on the project for the last four years. When we compare the results that we measure back in Monaco to the results that are reported by the Japanese scientists, they are in the vast majority of cases essentially the same. So this gives us a high degree of confidence in the data that's being reported by Japan generally. The observer team comprised of IAEA scientists and international experts from other labs closely watch the samples being processed. So the scientific approach used by your Japanese colleague is really state-of-the-art. What I can witness here is that the Japanese are really well organized and they do that very professionally. Local people, well skilled at handling a catch, help prepare the fish for analysis. Some of the minced fish is put into an on-site gamma ray spectrometer and some is sent overseas. As before, the fish, water and sediment will be tested by the labs participating in the international network and the results will be made publicly available. Data quality is important not only for science but also for environmental monitoring, for trade. Also it's important for radiation safety of people and the environment. And good data allows to have good management decisions.