The environmental group Blue Water Baltimore is investigating what it believes is a sewage spill at the Inner Harbor near the Domino Sugar Plant.

David Flores, the water quality manager for the group's Baltimore Harbor Waterkeeper program, said he inspected the area near Key Highway on his boat on Monday afternoon and believes, based on the odor and grayish appearance of the water, that a quarter-mile sewage discharge is stretching throughout the harbor, reaching areas near The Ritz-Carlton Residences and the Tiki Barge.

A spokeswoman for the city's Department of Public Works said Monday evening that a crew had looked but did not find any breaks or leaks. Spokeswoman Cathy Powell said the department would continue to investigate.

The Maryland Department of the Environment has not received a report of a spill, spokesman Jay Apperson said.

Flores said Blue Water Baltimore had received reports of the sewage first appearing on Saturday morning, after a severe storm of at least nine tornadoes dumped rain throughout the state. He said he was confident the incident is not merely algae.

"We have a big sewage spill down here," he said. "We've got people pretty alarmed about what's going on in the water. It's huge. It's covering up a pretty large section of the harbor. It's really, really big." He said he worried the sewage could exacerbate recent fish kills and algae blooms.

Luke.Broadwater@baltsun.com

Twitter.com/lukebroadwater