"Lead radiation shields forced on workers at the stricken Fukushima No. 1 nuclear power plant to cover their dosimeters masked radiation readings by about 30 percent."

"Tokyo Electric Power Co., operator of the plant, and Tokyo Energy and Systems Inc., a TEPCO group company, made the admission Aug. 8 after a test.

TES also acknowledged that when lead dosimeter covers were used on Dec. 1, eight of the subcontractor employees on the premises were working under illegal temporary staffing arrangements."

The Asahi Shimbun had the story August 9, 2012. [2]