The Japanese robot "Quince", who got stuck on the stairs leading to the Reactor 2 basement and had to be rescued by carbon colleagues back in June, completed a successful mission of entering the reactor building in Reactor 2, and this time climbing up the stairs to the 2nd and the 3rd floors, and measuring air radiation. The feat was accomplished on July 8.
TEPCO's handouts for the press on July 11:
Air samples taken on the 2nd and 3rd floor still have slight amount of iodine-131, and a lot of radioactive cesium. The measurement unit is becquerels per cubic centimeter.
TEPCO says the radiation is too high for human workers (up to 50 millisieverts/hour), which is a bit odd considering the company didn't have any problem sending in human workers into Reactor 1 which had the radiation level as high as 1,000 millisieverts/hour (or 1 sievert/hour) on the 2nd floor of the reactor building, and the 1st floor was not much better.
But that was back in the beginning of May. TEPCO's sudden unwillingness to have the workers risk radiation indicates to me that the company may be running thin on skilled workers with low radiation exposure, both at TEPCO and affiliate companies, and wants to conserve on the radiation dose for them. In the press conference on July 10 (morning), I heard them say they are not letting workers continue to work once they exceed 150 millisieverts of cumulative radiation exposure, even if the regulation has been relaxed to 250 millisieverts after the accident.