Decaying Arizona church undergoes revival : After more than 200 years, experts and volunteers are restoring Mission San Xavier del Bac’s artistic treasures.

TUCSON — The Mission San Xavier del Bac has been called the Sistine Chapel of the United States. It is this city’s signature example of its Spanish past, a booming tourist attraction and a parish church to Catholics of the Tohono O’odham tribe, who have worshiped there for more than 200 years.

But by the late 1980s, the church had sunk into such disrepair that parts of it were collapsing. The extent of the decay became evident in 1989, when plaster began falling off the walls around the sanctuary.

With that wake-up call, backers of the church launched a restoration effort that, at completion, will have taken eight years and cost about $1.2 million.

“It’s turned out to be a much bigger job than any of us imagined,” said Bernard Fontana, a member of Patronato San Xavier, a nonprofit preservation group formed to care for the mission.

This building has endured much since 1778, when Franciscan missionaries began 19 years of construction--using stone, fired brick and lime mortar.

The laborers who built it had to be given double pay because of the threat of Apache raids. In 1849, when gold-rushers stormed through southern Arizona on their way to California, many slept in the church nave and scratched their names on the walls before moving on.

The mission also has survived 35 years of abandonment, an 1887 earthquake, lightning, extreme desert sun and heat and misguided early repair efforts that included covering the roof domes in two layers of concrete.

Rain seeped in through the roof, which was in danger of giving way from weakness and the weight of the concrete. The walls were in bad shape as well, cracked and saturated with water that had leaked in but could not evaporate out.

But it wasn’t just the mission’s structure that was in peril. So were the paintings that cover its walls, a collection of frescoes that some believe make the mission one of the great art treasures in the country.

“If you look at all the Spanish Colonial art in the United States, you find nothing of this quality,” said Paul Schwartzbaum, head conservator of the Solomon R. Guggenheim Museum of Art in New York. “There’s nothing like it in Mexico either. The churches there were all neo-classicized later on.”

Restoration of the paintings began three years ago, with Schwartzbaum overseeing conservators from a prestigious Rome-based firm that has restored paintings by Raphael, Giotto, Cimabue and Titian.

The labor is tedious. The beauty of the paintings was lost behind two centuries of accumulated dirt that is being removed particle by particle. Results thus far have impressed visitors, many of whom do a double-take at the variety and richness of colors that only could be imagined before.

Even as the restoration crew goes about its work, tourists pour in. Outside, Latino and Native American worshipers walk toward the remote site on dusty desert roads that crisscross the Tohono O’odham Reservation.

Many make the pilgrimage daily. They sit and pray, seemingly oblivious to flashbulbs, crowds and construction dust.

The restoration is expected to be completed in 1997.

The Patronato is hoping to start an endowment. And because the mission has played such a central role in the lives of the Tohono O’odham, four O’odham workers are being trained to carry on its maintenance.

“I’m not a church person,” said Don Preston, one of the O’odham in training. “My church is outside, where the wind is. But I know this job is a big responsibility, and I’m glad I was chosen. The work is interesting every day. See these flowers here?”

He points to a portion of the choir loft wall. “Nobody knew they were there until we started cleaning off the dirt.”

The techniques that Preston and the other O’odham are learning are Old World--such as layering the walls with a mixture derived in part by boiling prickly pear cactus. The juice contains pectin, which gives the final mix a water-resistant quality. The new walls absorb rainwater, but it evaporates back out when the sun heats up.

The Patronato, an all-volunteer group, is raising the necessary funds through corporate and private donations. The money comes from contributors around the country, but most is from southern Arizonans eager to help bring an icon back to life.

“At first I was worried about getting enough in donations,” said Fontana, a retired historian who has lived near the church since 1956. “Then it took off and I realized that God or somebody is looking out for his building.”