The American Civil Liberties Union of Maryland sued an Eastern Shore volunteer fire company in federal court here today, claiming that it rejected a firefighter applicant because he is black.

The lawsuit, also signed by the Public Justice Center, a civil rights group, asks the court to bar the Princess Anne Volunteer Co. in Somerset County from racial discrimination and to award $125,000 in compensatory and punitive damages to the rejected applicant, James Mullen of Princess Anne.

Neither Mullen nor representatives of the fire company could be reached for comment.

C. Christopher Brown, an ACLU attorney in Baltimore, said that the fire company is all white, like many on the Eastern Shore, and that "membership procedures in these volunteer fire departments are such that black people just don't have a chance."

He said applicants to the Princess Anne fire company do not have to pass a physical or mental test but must receive affirmative votes from seven-eighths of "active members present and voting."

The Princess Anne fire company, Brown said, has a maximum allowable force of 45 firefighters. Thus, "at most," he said, "it requires six 'blackballs' to keep somebody out . . . . How likely is it that a black will ever get in at that rate?"

In its lawsuit, the ACLU said that the Princess Anne Volunteer Fire Co. is the "sole provider of fire protection services in the Princess Anne area." While it is a private, voluntary organization, the suit said, fire company members receive a $1,000 exemption from Princess Anne municipal taxes. The fire company "acts as a governmental entity," the suit said, and thus it is subject to government antidiscrimination provisions.

Gov. Harry Hughes issued an executive order in February barring volunteer fire departments from receiving state funds if they fail to certify that they do not discriminate. The executive order followed a recommendation by state Attorney General Stephen H. Sachs, who said he had received numerous reports from Eastern Shore blacks that they were systematically denied entrance to volunteer fire companies.

It could not be determined today if the Princess Anne fire company has received any state funds this year. About $4.2 million has been allocated for volunteer companies throughout the state to assist in buying fire engines, rescue apparatus and other equipment, but not all companies apply for such state funds.