SAN MARCOS -- The plight of undocumented workers has been a lifelong passion for Cal State San Marcos Professor David Avalos, and the issue has made its way into many of the artist's controversial works during his decades-long career.

But in Avalos' mind, a statement almost isn't worth making unless a lot of people know about it.

So back in 1988 along with collaborators Elizabeth Sisco and Louis Hock, Avalos unveiled a public piece of art on the back panels of 100 transit buses in San Diego.

Funded in part by the National Endowment for the Arts, the poster sarcastically dubbed America's Finest City "America's Finest Tourist Plantation," and featured a collage of photos of undocumented day laborers. A photo of a Border Patrol agent handcuffing two men dominated the piece.

The artwork embarrassed San Diego just as it was about to host its first big national event, Super Bowl XXII, and raised the ire of arts-funding critics. The poster is now part of California's history.

"At Work: The Art of California Labor," a traveling exhibit of various labor-themed artworks during the past century, debuted this month at San Francisco's California Historical Society and at San Francisco State University, and it includes the poster created by Avalos, Sisco and Hock.

For Avalos, the recognition is vindication of the original intent of the piece: to point out, amidst all the Super Bowl hype, that some of those contributing to the event did not have the same rights as others.

"San Diego couldn't host the Super Bowl without the tourist industry, and then, just as now, a lot of people working for them were undocumented workers," said Avalos, 56. "If they're good enough to work, they're good enough to be treated fairly and equitably."

The trio wanted to create public art, "but not a clump of bronze in a grass field somewhere," said Hock, now a professor at the University of California, San Diego. The public space they intended to use was not so much the ad space on the bus billboards as the public airwaves.

"We wanted to jump between the art pages and the front pages," recalled Hock.

Both the then-San Diego Union and the San Diego Tribune ran front-page articles on the billboards, and the Los Angeles Times and USA Today covered it as well. Local editorials blasted the work, which also inspired debate on local TV and radio stations.

"The media in a sense became one of our collaborators," said Sisco, who teaches at Southwestern College.

"At Work" is slated to travel across the state until 2007 and includes the works of prominent artists such as Dorothea Lange and Diego Rivera. Venues in Carlsbad and San Diego are negotiating to be part of the tour.

The poster was one of many collaborations that Avalos has done with Sisco and Hock over the years. In 1993, the three obtained another NEA grant for their work "Art Rebate/Arte Reembolso," in which the artists signed $10 bills and handed them out to undocumented workers at various locations countywide.

That work helped bring to a head the national arts-funding controversy, which was just one of many issues that led to the Republican takeover of Congress in 1994. Republican threats to strip the NEA of its funding, however, never materialized.

"Art Rebate" will be part of the "Work Ethic" art tour starting at the Baltimore Museum of Art in October. Venues in Des Moines, Iowa, and Columbus, Ohio, will also host the show in 2004 and 2005.

The media attention for "Art Rebate," though much of it was negative, did reap some positive effects, said Avalos, who has taught at CSUSM since 1991.

"People applauded the project," he said, "coming as it did when politicians like (former Gov.) Pete Wilson were pushing for Proposition 187, saying these day laborers were taking more money than they gave."

Prop. 187, a successful 1994 voter initiative that barred illegal immigrants from access to public services, was later nullified by federal courts.

"How many times have you driven up and down El Camino Real and seen trucks pull over and pick up a group of people?" Avalos asked rhetorically, pointing out that those apparent day laborers don't stand on roadsides "for a suntan. …

"They're paying payroll taxes using false Social Security numbers, and they'll never be able to collect -- they are due for a government refund."

The issue hits close to home for the Mexican-American artist, who grew up in a working-class family in a poor Mexican-American San Diego neighborhood. Avalos' mother was a maid and tortilla-factory worker; his father was a wharf builder.

The government money that Avalos, Sisco and Hock "rebated" to undocumented workers was but "a small sum of tax dollars that have been given as arts commissions," Avalos said. The discussion they wanted to generate with "Art Rebate" and other works is merely "a sign of a healthy society … the ability to have debate," he said.

"One of our chief critics, Bob Dornan, isn't even in office anymore," Avalos said.

"And Arnold Schwarzenegger is being reminded every day of the position he took (in favor) of 187," Avalos added. Wilson now co-chairs Schwarzenegger's gubernatorial bid.

"You can't have it both ways -- you can't invite undocumented labor to contribute to state coffers and don't give anything in return," said Avalos.