Omni House and one of its mentally disabled clients charged a Glen Burnie developer yesterday with housing discrimination.

Cromwell Fountain Associates canceled the sale of 12 apartments to the mental-health care provider earlier this month, according to a lawsuit filed in U.S. District Court in Baltimore.

In their suit, Omni House and James G., who would have lived in one of the apartments, said the cancellation violated federal fair housing law.

They have asked the court to prevent Cromwell Fountain Associates from selling the 12 units to anyone else until the Glen Burnie-based, non-profit rehabilitation organization for the mentally ill can plead its case.

The federal Fair Housing Amendments Act of 1988 prohibits discrimination in the sale of housing on the basis of disability.

John Pantelides, a spokesman for Cromwell Fountain Associates, said late yesterday afternoon he had not heard of the lawsuitand refused further comment.

Omni House agreed to pay $1 million for the two-bedroom condominiums, located on Ordnance Road between Ritchie Highway and Route 10, its attorneys said in a statement yesterday.

The health-care provider planned to move 24 clients there as part of a supervised housing program. More than 40 of Omni House's clients are enrolled in the residential program, including eight who currently live in Cromwell condominiums. The organization is trying to gain more financial freedom by buying homes instead of leasing apartments.

Cromwell Fountain Associates was aware of Omni House's plans when it accepted the contract on Dec. 20, 1990, the statement says.

The developer canceled the contract after residents in the development objected to the presence of mentally ill people, the attorneys say.

Chris Coile, president of Champion Realty Inc., said March 11 that the Cromwell Fountain condominiums are among the fastest-selling in the Baltimore area.