radioactive water in the basement might alternatively have come from the fuel storage pool. Highly radioactive water is also found in the turbine buildings of units 1 and 2. The US Navy sends a barge with of fresh water, expected to arrive after two days. Japan announces transportation will be provided in a voluntary evacuation zone of . Tap water is reported to be safe for infants in Tokyo and Chiba by Japanese authorities, but still exceeds limits in Hitachi and Tokaimura. Iodine-131 in the ocean near the plant measures 50,000 Bq/L, 1,250 times normal levels. Saturday, 26 March Fresh water becomes available again for use instead of seawater to top up reactor water levels. The fresh water is provided by two United States Navy barges holding a total of 2,280 metric tons of fresh water which were towed by the Japan Maritime Self-Defense Force from the United States Fleet Activities Yokosuka Naval Base to Fukushima. Radiation levels near the plant decline to a still relatively high 170 μSv/h. Sunday, 27 March Levels of "over 1000" and 750 mSv/h are reported from water within unit 2 (but outside the containment structure) and 3 respectively. Japan's Nuclear and Industrial Safety Agency indicate that "The level of radiation is greater than 1,000 millisieverts. It is certain that it comes from atomic fission ... But we are not sure how it came from the reactor." The high radiation levels cause delays for technicians working to restore the water cooling systems for the troubled reactors. USAF technicians at Yokota AB complete the fabrication of compatibility valves to allow the connection of deployed pump systems to the existing infrastructure at Fukushima. An aerial video recorded by a Ground Self-Defense Force helicopter reveals, according to NHK, the clearest and most detailed view of the damaged plant to date. Significant observations include: White vapour, possibly steam, emanating from the buildings of reactors 2, 3, and 4. The roof of the reactor 2 building has been badly damaged but is still intact. Monday, 28 March The Japanese Nuclear Safety Commission states that it "assumed" melted fuel rods in unit 2 have released radioactive substances into the coolant water, which subsequently leaked out through an unknown route to the unit 2 turbine building basement. To reduce the amount of leaking water, TEPCO reduced the amount of water pumped into the unit 2 reactor, from 16 tons per hour to