BALTIMORE (WJZ) — A mysterious substance in Baltimore’s Inner Harbor is raising a lot of eyebrows.

Blue Water Baltimore, a group that has a mission to “restore the quality of Baltimore’s rivers, streams and Harbor,” reports a “major pollution event” is being investigated at the Inner Harbor.

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They sent a scientist to the scene Tuesday afternoon after they received reports of cloudy plumes in the harbor.

The group says that it appears to have been caused by Baltimore’s storm drain system.

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It appears to be sediment in the water, but more testing has to be done to determine what exactly is in the water.

Baltimore Fire also tweeted Thursday afternoon that the unidentifiable substance is not a hazard or threat to anyone walking in the area, according to preliminary tests.

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