structure. A 62-metre-tall pumping truck, donated by Chinese manufacturer SANY is also used. April 2011 Friday, 1 April TEPCO says that groundwater near unit 1 contains radioiodine at levels 10,000 times normal, but NISA later disputes the numbers. The Japanese government is reported to be considering injecting nitrogen into the reactor vessels. Two more concrete pumping trucks, used initially to pump cooling water, are shipped to Japan from the Putzmeister factory in Germany. Saturday, 2 April TEPCO observes for the first time that contaminated water from the unit 2 is flowing into the sea. Workers discover a crack about 20 cm (8 inches) wide in the maintenance pit, which lies between the reactor 2 and the sea, and holds cables used to power seawater pumps. Workers were preparing to pour concrete into the crack to stop the water, which was emitting radiation at 1 Sv/h. Sunday, 3 April The attempt to plug the leak near unit 2 fails when the concrete fails to set. TEPCO then reattempts to plug up the trench that leads to the damaged storage pit with a combination of superabsorbent polymer, sawdust and shredded newspaper, which also fails. Radioactive water continues to leak into the sea. Radiation levels around the plant are estimated at 1 Sv/h and continue to decrease. TEPCO confirms the first deaths at the Fukushima facility, two workers who had been missing since 11 March and appear to have died in the basement of reactor 4 from bleeding due to multiple injuries inflicted by the tsunami. Japanese government officials say the Daiichi plant may continue to release dangerous radiation into the air for several months. Monday, 4 April TEPCO begins dumping water from storage tanks tainted with low levels of radioactivity into the Pacific Ocean on Monday night. Officials say this is needed to make room in a central waste facility to store water with a higher radioactive level. This more highly radioactive water is preventing workers from making progress on restoring the cooling and other systems to reactors 1–4. Samples of seawater near the plant reveal radioactive caesium at 1.1 million times the legal limit. The company says it could release up to 11,500 tons of radioactive water into the sea. A spokeswoman for Japan's Nuclear and Industrial Safety Agency says the less-contaminated water must be disposed of so that workers can secure a place to store more highly contaminated water on