A worker in his 60s from an affiliate company suffered a cardiopulmonary arrest (CPA) at Fukushima I Nuclear Power Plant on January 9, 2012 and was taken to a hospital in Iwaki City.
From Mainichi Shinbun (1/9/2011):
TEPCO announced on January 9 that a worker in his 60s from an affiliate company working at Fukushima I Nuclear Power Plant lost consciousness and collapsed while he was working, and suffered a cardiopulmonary arrest. His radiation exposure for the day was 52 microsieverts. No immediate information from TEPCO as to how long he has worked at the plant or what his cumulative radiation exposure is.
The worker was doing the concrete pour for the storage tank to store the radioactive materials from the contaminated water treatment since the morning of January 9. He fell ill at about 2:20PM, and was treated by a doctor at the medical room at the plant but he didn't respond to the treatment. At 4:30PM he was transported to a hospital in Iwaki City in Fukushima Prefecture. So far, three workers died of illnesses at the plant.
None of the "illnesses" has anything to do with radiation or with working at Fuku I, according to TEPCO.