WHEN Steve McNair was setting passing records at Mississippi's Alcorn State University, he was tagged ''Air McNair.''
If he plays as well in the National Football League, Air McNair could become as much a household name as Air Jordan.
But shortly after being drafted by the Houston Oilers, the rookie quarterback found that three San Diego television-station employees had applied for a trademark on his nickname, saying they hoped to strike a business deal with the prolific passer.
The US Patent and Trademark Office, however, turned down the Californians' application, saying the moniker was too closely associated with Mr. McNair. The quarterback had his nickname returned to him - and he learned a lesson in trademarks.
It's a lesson that's relevant to a growing number of people as applications for trademarks keep increasing - particularly for personal names. Last year, some 155,000 requests for trademarks were filed - 2-1/2 times the number filed a decade ago. Today, there are 727,983 active trademarks in this country, according to the trademark office.
The boom is in part the result of a windfall of new products, services, and companies. But lawyers who monitor the trademark sector say a growing number of people are getting the official federal seal of approval for their personal names - primarily for celebrity endorsements.
''My sense is, if you look at the last several years, there has been a clear increase in advertisers using well-known celebrities to sell their products,'' says professor Matt Millen of the South Texas College of Law. ''People are always trying to trade on someone else's goodwill.''
Ostensibly, the idea behind a trademark is to prevent confusion among consumers about competing goods and services. But where celebrity pitchmen are involved, the focus often becomes one of control.
A prime example is the Presley estate, which aggressively polices the use of Elvis's name or likeness, even going so far as to force an unauthorized Elvis Home Page off the computerized World Wide Web last year.
A similar situation may be unfolding in Texas, where the family of slain Tejano star Selena Quintanilla-Perez recently clashed with a Houston artist who painted a portrait of the singer. The painting, part of a Dia de los Muertos exhibit at a San Antonio art gallery, depicts Selena surrounded by skeletons and white roses.
The trouble began when artist Donell Hill - upon hearing that promotional posters reproducing her painting were being snatched up by the singer's fans - decided to sell lithographs of the painting.
Days before printing, Selena's family erupted in anger, calling Mrs. Hill's painting ''trashy'' and threatening to sue if any lithographs were sold. Selena's estate, managed by her father, Abraham Quintanilla Jr., claims sole rights to the singer's name and likeness.
The original work is still up for sale, but Hill has halted plans for the lithographs and changed the painting's name from ''Selena's Silent Song'' to ''The Silent Song.''
THIS is not the only run-in the Quintanilla family has had with the use of their daughter's name or image for commercial use, though.
Two days after her death, says Selena's uncle, Eddy Quintanilla, ''there was this guy with Mississippi license plates in a truck in front of her house selling T-shirts. You have to kind of control what kind of stuff if it has to do with her. Or there are people that will do unbelievable things.''
Despite Hill's frustration over not being able to print copies of her painting, she says she can empathize with the family.
The artist became the unwanted center of national attention herself last year when a Roman Catholic art gallery in San Antonio shut down her ''Spiritual, Sensual, Sexual'' exhibit after an archbishop went on television, calling her work ''pornography.''
Hill, who signs her artwork with only her first name, says the incident was recounted in ''Playboy'' and ''Libido.'' People began to refer to her as an erotic artist. ''I didn't want people to always carry the notion that my work is pornographic,'' she says.
So to protect herself, she may seek a trademark on ''Donell.''