TOKYO, Japan (AFP) — An estimated 5,500 liters of radioactive water leaked from Japan’s stricken Fukushima nuclear plant but no sign of contamination has been detected outside the facility, its operator said Thursday.

A spokesperson from Tokyo Electric Power Company told Agence France-Presse that the leak was detected at part of the plant that processes contaminated water.

“We estimate that roughly 5.5 tons (5,500 liters) of water leaked” on Wednesday morning, but “there have been no significant changes” at posts monitoring radioactivity around the power station, she said.

Even so, TEPCO plans to remove soil from around the area that may have been contaminated, the spokesperson said, without providing specific details on the location of the leaked water.

Wednesday’s leak took place at a facility which processes the water before most radioactive elements are filtered out at a different, advanced facility known as ALPS.

TEPCO said the leak from a vent was spotted by a worker who was cleaning the vent before operating the facility.