A Bladensburg man has filed suit in federal court here seeking $1 million for injuries he suffered in a 1974 car accident involving a former assistant naval attache for the Soviet Embassy in Washington.

One of the issues in the case is whether a foreign official loses his diplomatic immunity when he returns to his home country.

The civil suit was filed by Floyd Howard Dickerson III, 26, who claims he was left permanently injured as a result of the car accident.

The suit contends that Georgiy B. Mashkouskly, a Soviet resident attached to the embassy in 1974, slammed into the rear of a car in which Dickerson was a passenger on July 21, 1974.

The accident, which took place on U.S. Rte. 50 in Anne Arundel County, left Dickerson, of Volta Avenue, with "serious injury to his body and severe shock and injury to his nervous system" according to the brief filed in the U.S. District Court.

The suit says Dickerson, an automotive mechanic, continues to suffer great physical pain and some permanent disability from the injury.

The American Insurance Company, which handles the automobile account for the Soviet Embassy, claims Mashkouskiy has diplomatic immunity from suit, according to Dickerson's attorney.

Mashkouskiy was returned to the Soviet Union late last year. His attorney, Charles C. Bowie of Rockville, cannot be reached until July, according to his secretary.