Tokyo Electric Power Company Holdings Inc., operator of the crippled Fukushima No. 1 power plant, has been revising guidelines for when workers need to wear full masks with hazmat suits or less-bulky outfits to improve their working conditions during the scorching summer.

While a full-body outfit limits radiation exposure, hazmat suits and full masks have been a heavy burden for workers because they restrict movement and make it difficult to breathe, prompting Tepco to revise the guidelines on their usage.

In March, Tepco changed the guidelines, dividing the premises into three areas.