Stoner Broadcasting System Inc., an Annapolis-based company that owns 12 radio stations in the United States, has acquired a 10 percent interest in a British radio company for $2.5 million in cash.

Stoner is considering buying more of the British firm, Metro Radio, to take advantage of opportunities arising out of the European economic unification planned for 1992, said Bill King, Stoner's chief financial officer.

British law will restrict Stoner to holding no more than 20 percent of Metro Radio's stock, and European countries have similar restrictions that are expected to remain in force after 1992, King said.

However, he said, the European Community's economic unification will open up acquisition possibilities for radio companies based within the EC, and Stoner hopes to benefit through its stake in Metro Radio, which has three stations in the Tyne, Wear and Cleveland areas of Britain.

Stoner owns stations in Des Moines; Louisville; New Orleans; Knoxville, Tenn.; Dayton, Ohio; and Binghamton, Buffalo and Rochester, N.Y. King said the company is looking for domestic acquisitions as well.

Gap Inc. of San Bruno, Calif. said it will begin construction of a 600,000-square-foot distribution center on 70 acres in Harford County outside Baltimore by late 1991. The clothing retailer has an option to acquire another 35 acres, and may later expand the facility, a company spokesman said in a statement.

The Gap, which also has distribution centers in Kentucky and California, said it will be a major employer in the county, although specific job totals were not released.

Centennial Contractors Inc. of Vienna won contracts valued at more than $11 million for renovations at Luther Jackson Intermediate School and Frost Intermediate School.

Integrated Health Services Inc. of Hunt Valley acquired major components of Affiliates Group Inc. of Nashville, including its subsidiary, Professional Community Management Inc. of El Toro, Calif. The transactions are valued at $12.35 million, according to a company statement.

DeLeon & Stang, C.P.A. of Gaithersburg acquired Dennis W. Davis, C.P.A., P.C. of Arlington for an undisclosed amount.

Clement International Corp. of Fairfax received a subcontract from O'Brien-Kreitzberg & Associates of New York to develop an asbestos management policy for the New York Metropolitan Transportation Authority.

RDA Consultants Ltd. of Hunt Valley, Md., won contracts from EME Inc. of Rockville, General Research Corp. of Vienna and American International of Pittsburgh to provide software.

The Sugarloaf Agency of Germantown gained the marketing contract for Kenneth Allen Communities, a developer of single-family houses in the Washington area.

Nasuti & Hinkle of Bethesda received an advertising and promotions contract from Epicurean Events of Vienna.

Eisner, Petrou & Associates Inc. of Washington received the public relations contract for Fair Lanes Bowling Inc. of Baltimore.

Eisner & Associates Inc. of Baltimore won advertising accounts totaling $2.5 million from Farmers & Mechanics National Bank of Frederick, Fair Oaks Hospital of Fairfax, Lakeside Shopping Center of Sterling Heights, Mich., and Williamsburg Group of Williamsburg.

Fulbright & Jaworski, an international law firm based in Houston, opened an office in Washington with 80 attorneys.

Martin Schaffer Inc. of Bethesda was awarded an advertising contract by the Imaging Products Group of Dynatech Laboratories Inc. of Chantilly.

National Consulting Strategies Inc. of Silver Spring received a six-month public relations contract from the Washington chapter of Physicians for Social Responsibility.

Newbridge Networks Inc. of Herndon was awarded a contract by the Orange County Register of Orange County, Calif. to provide an integrated voice and data network.

Nicholas & Associates of Ellicott City received a contract from General Physics Corp. of Columbia to assess its 401(K) profit-sharing plan.

Life Technologies Inc. of Gaithersburg began a recycling program for plastic foam containers.

APCO Associates of Washington, a consulting subsidiary of the Washington-based law firm Arnold & Porter, opened a western division in Denver.

SignMasters Inc. opened in Rockville.

Shad Ahmad, former comptroller for the Information Industry Association, opened an accounting firm in Arlington.

Glass Blocks of Virginia opened in Springfield.

The Center for Development Inc., a nonprofit research center addressing growth problems in developing countries, opened in Alexandria.

Announcements of news and developments affecting Washington area companies should be sent to Regional Report, Business News Department, The Washington Post, 1150 15th St. NW, Washington, D.C. 20071.