Levels of radioactive substances have surged once again in the groundwater surrounding the crippled Fukushima nuclear power plant, the Tokyo Electric Power Co. said on Tuesday.

The rates show that radioactive contamination is quickly spreading in the disaster area despite ongoing efforts to decommission the site, with levels of cesium-134 and cesium-137 as high as 90 times greater than they were just three days prior.

“We still don’t know why the level of radiation surged, but we are continuing efforts to avert further expansion of contamination,” a TEPCO spokesman stated.

TEPCO says that it is now attempting to determine if the substances are seeping into the ocean, a possibility that is very likely, as the Japan Times reports:

The substances, which were released by the meltdowns of reactors at the plant in the aftermath of the huge tsunami of March 2011, were not absorbed by soil and have made their way into groundwater.

Subsoil water usually flows out to sea, meaning these two substances could normally make their way into the ocean, possibly affecting marine life and ultimately impacting humans who eat sea creatures.

The site of the nuclear disaster has been plagued by a series of storage tank leaks among a list of other mishaps this year.

Last month, similar reports had surfaced showing spikes in radioactive substances in the groundwater.

The news arrives as several nuclear reactors in Japan moved closer to restarting this week, with four utility companies applying for safety inspections for 10 idled plants—or what the Associated Press called "the clearest sign of a return to atomic energy almost two and a half years after the Fukushima disaster."

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