Six workers at the Fukushima No. 1 nuclear plant were doused Wednesday with radioactive water from a desalination system, Tepco said.
The fluid splashed onto the men when they accidentally removed a pipe connected to the system, officials from Tokyo Electric Power Co. said.
The highly toxic water spilled out in the incident, covering the desalination facility’s entire floor, Tepco said.
About 10 tons of water may have leaked, the utility said, noting the pipe in a reading in August contained some 37 million becquerels per liter of radioactive substances that emit beta rays such as strontium-90, against the legal limit of 30 becquerels for strontium-90.
The mishap is the latest in a spate of leaks and problems caused by human error that have added to public criticism of Tepco’s handling of the crisis.
“The water did not come into contact with their faces so there is little possibility that the workers ingested” any of the water, a Tepco spokeswoman said, adding there were five other workers present at the time.
The pipe was reconnected and the leak stopped within an hour of the initial incident, the utility said in a statement.
The system is designed to desalinate contaminated water once it has been treated to reduce its cesium content. It is then stored in tanks on the site.
Wednesday’s incident will do little to improve the commonly held view that Tepco is making a mess of handling the crisis.
Earlier this week it was revealed a worker had accidentally switched off power to pumps keeping broken reactors at a steady temperature.
Tepco workers have been pouring thousands of tons of water onto the reactors to keep them cool.
The radioactive water is being stored in around 1,000 tanks, which have recently been the source of leaks.
Tepco has so far revealed no clear plan for the water stored on the site, but experts have said that ultimately it will have to be dumped in the Pacific once it has been scoured of the worst of its radioactive load. But this suggestion faces opposition from fishermen, environmental groups and neighboring countries.