BALTIMORE, SEPT. 18 -- The arrest of real estate developer and racetrack owner Mark Vogel on cocaine possession sent waves of concern through the racing industry today. But racing officials said it is too early to gauge the effect it will have on the state's harness tracks, both of which Vogel owns.

Vogel, 42, was arrested last Thursday night and charged with possession of cocaine after Fairfax County police stopped his Corvette on Georgetown Pike near Great Falls and found four grams of cocaine. Vogel was released on $10,000 bond.

The dissolution of Freestate Raceway this year left Vogel in control of Maryland's harness tracks, Rosecroft Raceway in Oxon Hill and Delmarva Downs in Berlin, near Ocean City. (For many months, Vogel also has been trying to secure financing to purchase Atlantic City Race Course on the New Jersey shore.) Members of the Maryland Racing Commission, which oversees the industry, said they learned of the arrest this morning and were reluctant to comment pending resolution of Vogel's case. Several expressed concern, if not surprise.

"I'm very, very worried" about what this might mean to Maryland racing, said Ernest Colvin, commission chairman. He said the commission has begun its own investigation "to find out a certain direction we might take," but said no action likely would be taken before Vogel is tried.

"We can't be hasty," said commissioner Jack Mosner. "We have to wait until we get the facts to go any further."

According to Bruce Spizler, assistant Maryland attorney general who specializes in racing, the racing commission would have authority to revoke or suspend Vogel's license to operate the tracks if he were convicted of the possession charge.

"There is nothing we can do other than to wait and see if there's a conviction," Spizler said. "If there is a conviction, the commission could be faced with a difficult decision."

Vogel has not been an active policy-maker since he entered the racing scene by purchasing Rosecroft in December 1987, relying heavily on staff and particularly his top-ranking executives -- first Bill Miller, then Jim Murphy -- but he has shown a certain commitment to the industry. He spent more than $2 million on improvements at Rosecroft, enlarging the racing oval to five-eighths of a mile, creating a "EuroTrack" by banking the turns (which reduced track bias) and installing a new lighting system.

His arrest could signal one of the perils of monopolistic ownership, considering the state has no alternate site if such a need should arise.

Charles Lockhart, executive vice president of the Cloverleaf Standardbred Owners Association -- which represents harness drivers, owners and trainers -- said he received a number of calls this morning from horsemen anxious about the impact of Vogel's arrest.

"Obviously, we're concerned about racing, and that racing continues in the state," Lockhart said. "But it's business as usual for the time being. I don't know what this all means as far as Vogel and track ownership, but we're going to do whatever is necessary to keep racing going."

Colvin said he considers Vogel a "responsible" racetrack owner but declined further comment. "The man is in trouble," he said, "and for me to comment might not be appropriate."