"It's really painful," said the 61-year-old artist whose works depict Angeleno life from Mexican heritage to the dangers of drugs. "People say 'don't take it personal,' but it's totally personal. They're my babies."

At one time hosting an estimated 1,500 pieces of wall art, Los Angeles is the nation's mural capital, but that's a fading distinction thanks to prolific graffiti taggers, a legal morass over classifying the artworks as illegal signs, and neglect.

"I never thought 30 years ago that I would have to save works from being destroyed," said muralist Judith Baca, an art professor at the University of California, Los Angeles and founder-artistic director of the Social and Public Art Resource Center, which promotes and protects murals. "We've had to defend one piece after another."

Spawned in the '70s on the city's eastside, LA's murals form a kaleidoscope of color and imagery in a city known for bland urban sprawl. Decorating unlikely swaths of concrete ranging from housing projects to freeway underpasses, some are so massive they are best viewed blocks away, while others are easily digested in a drive-by glance.

They pay homage to celebrities — Anthony Quinn as "Zorba the Greek" towers over a downtown parking lot, Steve McQueen stares out from the side of a house. Some celebrate civic milestones such as the 1984 Olympics or institutions like the Los Angeles Chamber Orchestra. The mother of all, Baca's "The Great Wall of Los Angeles," is a half-mile (1 kilometer) stretch of California history along a San Fernando Valley drainage canal.

Others are displays of immigrant pride and ethnic history or abstract visions and palettes of pop art blanketing the sides of corner stores and businesses in blue-collar neighborhoods. "They're a reflection of us and who we are as a city," said Pat Gomez, the city's murals manager.

Most of the murals — some 1,100 — are located on private property, while 400, created as part of the city's mural program that ended in 2006 in a municipal budget crunch, are mostly on public land.

The exact number of lost murals is hard to determine. Baca's group inventoried a sample of 105 city-sponsored works, and found 60 percent had vanished. Baca said they're disappearing with increasing frequency since the mural program, which included maintenance, died. The city plans to do its own survey, Gomez said.

Graffiti is blamed as the biggest culprit. Murals are often targeted by vandals because the city does not regularly remove tags from murals so the spray-paint scrawls remain indefinitely. Blank walls are easier to clean and are whitewashed by city workers within days.

In the case of private property, the city requires the owner to remove the graffiti or face a fine. Sometimes, the owner removes the mural, too, to avoid repeated citations.

For freeway murals, the state Transportation Department requires artists or others to pick up the $3,000 tab to erect barricades for the cleanup work, money which artists don't often have.

"When is it the job of the individual artist to maintain a public work?" Baca asked rhetorically.

De la Loza has fought numerous battles to save his murals.

After his favorite work celebrating Latino diversity, "City of Passion," was painted over by the city because it was deemed "too ethnic," he sued. He won a $52,000 settlement and the right to restore the mural, which had been saved under a protective coat beneath the whitewash.

But only months later, hieroglyphic markings denoting gang turf were choking the brilliant colors of the work. The city whitewashed the wall and planted vines to prevent more graffiti.

De la Loza, who has painted murals amid gang shootouts and triple-digit temperatures, was devastated. "This is brutal, physical work," he said. "There's no appreciation of that."

In rare instances, gangs have left murals alone. One South Los Angeles community center managed to get local gangs to agree not to tag its mural, largely because gang members use the center.

Baca has been pressuring the city to address the graffiti problem for years. She advocates setting aside 1 percent of the roughly $40 million a year the city and county spend to remove graffiti for mural-cleaning, making vandals remove their work, and giving taggers their own wall space to paint.

So far, her proposals have fallen on deaf ears. The city is moving ahead with a proposed ordinance to preserve murals, but it does not address removing graffiti from the art, which is more time consuming and costly because the artist must be present and the original artwork touched up.

It would, however, save murals targeted by city building inspectors as "illegal signs" because they were either painted during a citywide billboard ban or do not conform to size and location rules governing signage. The issue is that current city rules do not differentiate between commercial signs and fine art murals.

Some 60 murals face removal or daily fines under signage violations. Some, like "Under the Moon" on the side of an eastside retail store, have already been whitewashed. The property owner painted over the piece, which depicted a Mexican immigrant's journey to the United States, rather than go through a costly appeal process, said mural designer Stash Maleski.

The proposed ordinance would resolve that issue by treating murals apart from billboards, issuing mural permits and requiring works to be protected with an anti-graffiti coating, a type of wax that allows spray paint to be cleaned off with a pressure hose, Gomez said.

But it would also classify any digitally made wall art as billboards. Baca said digital technology is the answer to saving murals. The works can be scanned into a computer and printed on large vinyl sheets that are adhered to walls, allowing for easy removal and wipe-off cleaning.

"It's indistinguishable from paint," she said, pointing to her latest works: two indoor digital murals of the namesake of the new Robert F. Kennedy Community Schools in Los Angeles.

Until the city better protects outdoor murals, Baca said she's not doing further projects in Los Angeles.

De la Loza presses on. Although his work is increasingly a heartbreak, he loves painting the monumental works that carry symbolic meaning for the masses. His latest work is a 130-foot (40-meter)-long piece called "Faces of the Americas" recently mounted on a South Los Angeles library.

"Murals are the voice of the people. They teach history, they give hope," he said. "It's just a constant struggle."