Attorneys for two casinos planned along the Delaware River sued the city yesterday, and the Greater Philadelphia Chamber of Commerce is expected to join the fight soon.

The SugarHouse Casino in Fishtown and the Foxwoods Casino in South Philly asked the state Supreme Court to strike from the May 15 ballot a referendum that would allow voters to decide where the casinos are built.

The casinos joined a lawsuit filed last week by the state Gaming Control Board, which claims that the referendum illegally conflicts with the state law that gives it sole control over where casinos are located in the city.

SugarHouse spokesman Dan Fee yesterday called the referendum "substantively illegal and procedurally defective."

The referendum proposes a change to the Home Rule Charter to ban casinos from within 1,500 feet of homes, schools, churches, parks and other public spaces.

"Changing our charter is an important and serious matter, and there is a reason there are strict procedures and mandates," Fee said.

"Unfortunately, this process has not followed those rules and the referendum should not go forward."

The chamber of commerce yesterday confirmed that its attorneys will soon file a legal brief to support the Gaming Control Board's challenge to the referendum.

"When you look at the law, which was properly passed, it gives one entity [the gaming board] the right to site the casinos," chamber spokeswoman Mary Flannery said.

City Councilman Frank DiCicco said he expected the casinos to sue, but found the chamber's anticipated action "disturbing."

DiCicco, who has led Council's efforts to rein in casinos, said he understands the chamber may be eager for gaming taxes that will be used to expand the Pennsylvania Convention Center.

But he worries that small businesses - especially local taverns - near the casinos would suffer serious impacts.

"What do you think is going to happen to those businesses? They're going to go under," DiCicco said.

Also yesterday, the Supreme Court gave Council a 10-day extension to file arguments for a challenge to the board's December decision on casino locations here.

Other challengers, including Casino-Free Philadelphia and a coalition of four riverfront civic groups, filed motions yesterday.

Those groups claim the Gaming Control Board failed to consider the environmental impacts of the proposed casinos and accepted substantial changes to the casino plans long after the public's right to comment ended last year.

Maurice Mitts, Council's attorney, is pushing for more information.

Mitts said the gaming board has said that some of the information he wants is confidential and will be released only if the two casinos give the OK.

"That is an outrageous situation," Mitts said, adding that the Supreme Court can't do its job if the Gaming Control Board won't release all of its information.

The court ruled that Mitts first must prove that Council has the standing to challenge the Gaming Control Board's decision before it will rule if the confidential information must be released. *