Xcel Energy’s Monticello nuclear plant leaked 400,000 gallons of radioactive water, although regulators say there’s no danger.

According to AP News, regulators have been monitoring the Xcel’s cleanup efforts surrounding the radioactive water leak, saying the company took swift action to address the issue.

The company evidently reported the leak of tritium-contaminated water to federal and state authorities in late November, but the public was not informed until this week.

“We knew there was a presence of tritium in one monitoring well, however Xcel had not yet identified the source of the leak and its location,” Minnesota Pollution Control Agency spokesman Michael Rafferty said.

“Now that we have all the information about where the leak occurred, how much was released into groundwater, and that contaminated groundwater had moved beyond the original location, we are sharing this information,” he said, adding the water remains contained on Xcel’s property and poses no immediate public health risk.

The company says the leak poses no danger to people or the environment.