BALTIMORE (WJZ)– A strange smell is taking over the Inner Harbor. Now, an environment group think it has pinpointed the cause.

Monique Griego has more on what may be causing this stinky problem.

The problem isn’t only in the air, it’s also in the water.

The Inner Harbor is being overpowered by an abundance of trash, dead fish and an overwhelming odor.

“We woke up in the morning and we smelled sewage,” one Baltimore resident said.

At first, the smell and dark water were blamed on an algae bloom. But this week, the mystery surrounding what’s causing it widened after the odor got worse.

“We know what algae smells like– it smells horrible. But this smells like sewage. It’s different,” said Tina Meyers of the environmental group Bluewater Baltimore.

Meyers says all signs point to a sewage leak or an overflow of the system, possibly caused by last week’s storms.

Boat crews noticed the problem Saturday.

“Basically, it was just a field of gray water sitting on top of the harbor,” David Flores of Bluewater Baltimore said.

The first things that tipped Meyers off that sewage may be in the water were what may look like rocks. But they’re actually balls of grease. Meyers says they can only form in sewage lines, and when you crack them open, they stick.

And there are other signs.

“It’s disgusting, but tampon applicators, condoms– people flush all kinds of things,” Meyers said.

They’re collecting samples to test for bacteria found in sewage. The state and city are also doing their own testing, but have yet to confirm or deny it’s sewage.

Department of Public Works (DPW) crews are also out looking for leaks, but so far no cause has been found.

“I admit it’s really baffling where the source is because it was such a massive spill and it hasn’t been obvious,” Meyers said.

Bluewater Baltimore is hoping to get their samples back Wednesday night. WJZ will let you know the results.

They’re asking anyone who notices a problem at the Inner Harbor to call 311, because the faster they can get out, the easier it is to find the cause.