A former Naval Academy classmate of President Carter recently changed his name from Robert Earl Lee to the Spanish-sounding Roberto Eduardo Leon and now is eligible -- as a minority -- for preferential treatment under Montgomery County's affirmative action program.

Leon, 56, a retired Navy captain who works in the county Environmental Protection Department's Pollution Control Division, legally changed his name Feb. 21 and immediately requested that he be reclassified as a member of a minority group, a change granted last week. Under county guidelines Leon's Spanish surname makes him eligible for promotion over other white males.

"He has a knack for figuring out loopholes in things," said Eric Mendelsohn, Leon's boss, "Bob, I mean Roberto, is a highly regarded professional, a little eccentric in some ways. It's nice to have a Hispanic on our staff."

Leon, a $27,857-a-year engineer, surprised the County personnel office by filling out a form requesting that his race be changed from 01, white, to 03, Hispanic.

"It's confusing, I know," he said yesterday, adding that he had been considering the name change "devez en cuando " (from time to time).

Although he denied achieving minority status for job-related reasons, Leon is clearly aware of the ramifications.

"I've already applied for several jobs. I feel at ease with it as long as everyone else does," he said.

But the prospect of Leon being promoted over other white males has "raised some eyebrows" in the office, according to Mendelsohn. Says Leon, "If that's the law, that's the law. You've got to go along with it."

Mendelsohn said Leon "is the type that would probably push it" -- even to the Supreme Court if necessary. "To my knowledge, he's the only one that has tried this. Now, of course, there may be more doing it f they think it's an advantage," said Mendelsohn.

The supervisor said he was not aware that Bob Lee had become Roberto Leon until he returned from a recent vacation and heard his employe "saying hello in Spanish."

Of the 35 employes in the Rockville office, two belong to minority categories -- one black woman and Leon, who joined the county government in 1975.

"I was brought up in the Southwest," he explained yesterday," with lots of Spanish influence. I took Spanish in high school. And my grandfather was of Spanish origin."

Leon also said that he wants to retire in Chile and "when you live in a particular culture, you should adapt. It would be easier for me to blend in" with a Spanish surname.

The divorced father of two tells the story of Chilean folk hero Bernardo O'Higgins. "Now if he came to America, he wouldn't be Hispanic. It's all very curious."

Leon's story surfaced last week in a Montgomery Journal article by staff writer Ruth Hepner.

Under the county's affirmative action program, each department must employ a certain number of members of minority groups in each job classification. As an acoustical engineer, Leon would be competing against others in the classification listed as "other professionals."

If the department is found to be underrepresented by blacks, women or other minorities, they would take precedence over equally qualified white males.

Leon's department currently is not underrepresented so he would not have an advantage over other employes. However, Mendelsohn said yesterday that Leon would not seek a promotion in his current job "because he's just about at the top" but would definitely have an advantage in seeking another appointment in some county office that does not have the required percentage of minorities.

Although the federal and some county governments have given up the "Spanish surname" designation in favor of the word "Hispanic," Montgomery County's affirmative action program defines minorities as "black, Asian-American, American Indian, Spanish-surnamed and other [Aleuts, Eskimos, Malaysans]."

"I haven't thought about it much," said Leon. "But I guess other people are pretty concerned about it. I've applied for jobs just like anybody else would. I'd like a new challenge."

Leon's paycheck and personnel records already reflect his new name, but he said "It takes time" to complete the formal process, including changing credit cards and identificaiton papers.

"Fortunately, I still have the same initials. So the monogrammed towels -- if I had them -- wouldn't have to be changed."

Born in San Diego, Leon said his grandmother -- whose maiden name was Lee -- told him that his grandfather was Spanish.

Leon said he does not know Jimmy Carter "personally" but remembered him from the Naval Academy and has seen Carter "at a couple of class reunions."

Leon said his friends have taken the surprise Spanish surname in stride. "Some call me Roberto, some call me Bob. I'm very flexible."