A river near the Siberian town of Norilsk turned bright red on Tuesday, stunning local residents and puzzling authorities. Some locals, though, are saying this isn’t the first time the Daldykan River has changed color suddenly. Russia’s Ministry of Natural Resources and Environment is suspicious that a nearby metal plant may have leaked an “unidentified chemical” that caused the water to change colors, but a full investigation has been ordered to find out why local residents are seeing red.

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The plant in question is the Nadezhda Metallurgical Plant owned by Norilsk Nickel, the world’s largest nickel producer. In a statement issued Wednesday, Russia’s Environment Ministry suggested that the plant may have leaked chemicals if a pipeline was broken, fueling the theory about the cause behind the color-changing river water. So far, the company has denied all suggestions that the plant’s operations or pipelines could be involved in the mysterious red water.

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If there can be a silver lining on a story about possible industrial pollution, nearby residents are not under immediate threat, as there is no public water utility connected to the river, the Norlisk city administration told state news agency Sputnik. The town of Norlisk, though, is known for having immense problems with pollution, and until the exact cause for the color-changing river is known, nobody can say with certainty what the extend of the risk might be. Russia’s Environment Ministry will continue its investigation and, in the meantime, locals will continue to post images of the blood-red river on social media.

Via CNN

Images via Facebook/reposted by Russian media