A pair of Baltimore residents filed suit Monday accusing the city of breaking the law by allowing toxic chemicals to leach into the Patapsco River from the South Baltimore site where a casino is now under construction.

The lawsuit is the second to raise environmental concerns about development of the Horseshoe casino on Russell Street. It contends that the city's deal with CBAC Gaming, a coalition led by Caeser's Entertainment, exposes city taxpayers to having to pay for cleaning up contamination from the site.

The suit was brought on behalf of Michael J. Finck, who lives across the Middle Branch less than a mile away from the casino site, and Mark E. Richardson, who lives farther away in Federal Hill. Their lawyer, G. Macy Nelson, said his clients are not members of any environmental organization, but care about the river.

"We don't want money from the city, we want the site cleaned up," said Nelson, a Towson attorney who often represents plaintiffs in environmental cases.

Finck and Richardson, joined by two others, also have warned the city formally that they intend to file another suit in federal court for allegedly allowing toxic chemicals to get into the Middle Branch via storm drains that empty into the river from the site, where a chemical factory and other industries once operated.

George Nilson, the city solicitor, said he had not seen the new lawsuit, but likened the flurry of litigation over the casino project to "a plague of locusts."

"I continue to wonder what the real motivation in all of this is,'' Nilson said. "I'm sure it's not clean air and clean water."

He added that he suspected the real purpose had to do with gambling rather than the environment and suggested the residents' distance from the site may undermine their legal claims.

A group of Westport residents backed by a foundation filed suit in February contending that the city, state and casino developer colluded to skirt state and federal requirements for cleaning up the site. A city circuit judge refused to block casino construction, but the lawsuit financed by the Inner Harbor Stewardship Foundation remains pending.

William B. Canfield III, counsel for the Washington-based foundation, said he had spoken with Richardson earlier this year because he'd heard the Federal Hill resident was concerned about the casino's impact on the river. But Canfield said the foundation was not behind the new lawsuit.

Richardson said by email Monday that he was too busy to discuss the case. Finck, who keeps a boat at a Middle Branch marina, said he joined the lawsuit after hearing about the site's contamination.

Nelson said that Finck and the two suburban residents he is representing in the matter "spend a lot of time on the river" and want to stop the pollution fouling it.

"Our grievance is with the city, not with the casino," Nelson said.

In their suit, Finck and Richardson contend that the city is violating state law because arsenic, trichloroethylene and other toxic pollutants in the soil on the former chemical factory site are getting into the ground water, which then seeps into the river. They argue that "the city has undertaken no meaningful effort" to clean up the site or to keep pollution out of the ground water or the Patapsco.

The city and CBAC Gaming have pointed out that the Maryland Department of the Environment approved the developer's plan to cover the contaminated ground at the site with new buildings, pavement and clean soil. The state also ordered the developer to take precautions to prevent toxic vapors from entering or building up inside the casino.

But Nelson said the state-approved plan to cap the site "does not address the soil contamination, and it does not address ground-water contamination."

The lawsuit contends that the casino developer's deal with the city leaves taxpayers exposed, because it says CBAC Gaming can walk away from the project if environmental costs exceed $2 million, or else it could reduce its lease payments to the city by up to $1 million.

tim.wheeler@baltsun.com