On May 26 Tepco finished dismantling the 56 tanks from the H4 tank farm. Tepco mentioning some soil remediation having being done, but providing no details about it.
Those tanks were used to contain contaminated water and sludge from the reactors and the contaminated water treatment systems.
Those tanks panels having not been welded but only bolted with rivets, caused numerous leals in 2013. Those tanks panels were removed and sent to an automated cutting system for further dismantling and storage as radioactive waste. Their content was transfered to other more recent tanks, those welded.