It’s a race against time to save Utah’s salt flats : Speed enthusiasts and a mining company are trying to replenish Bonneville’s legendary mineral expanse.

The Bonneville Salt Flats glow at first light, an eerie incandescence that hardens to dazzling white. For miles in all directions, there is only the salt--a great white sheet dropped in the bleak desert.

For a few days each summer, the rising sun over the salt flats is met by the whine of high-performance engines. Men have come here to test machines, nerves and driving skill on this oddity of nature since America fell in love with the automobile and discovered that no man-made track beats hard-packed salt. Nearly all land-speed records have been set here.

But the era of high-speed racing on the salt may be nearing an end. Utah’s world-famous Bonneville Salt Flats are disappearing.

Once up to seven feet deep over 96,000 acres, the salt now covers only 19,000 acres, with mud showing through in places. By some estimates, the salt is disappearing at a rate of 1% a year and may be gone in a few decades.

So much salt has been lost that racers have been forced to cut its 11-mile drag strip to just five miles in recent years. The shorter track, roughened by potholes and pressure ridges, means slower speeds.

On July 1, exactly 25 years after the salt loss was first documented, a coalition of car enthusiasts, scientists and corporate officials launched an effort to repair the damage by replacing the lost salt over 28 square miles. No one is sure it will work, but for racers, naturalists and others who treasure the salt flats, anything is worth a try.

“We can barely race on it right now, and there’s nowhere else to go in this country that offers that limitless expanse of salt,” said Mike Waters, vice president of the Southern California Timing Assn., adding that if the project fails, racing there will be over.

The Bonneville Salt Flats have captured the imagination of a car-crazed world since the first land-speed record of 141.7 m.p.h. was set here in 1914.

The salt, residue from an ancient lake that once covered much of Utah, compacts to a surface smoother than concrete. Its featureless terrain also gives miles of track needed to reach high speeds with no danger of smacking into something should a driver lose control. “If you lose it at 400 m.p.h. and start to spin, you just spin and spin until you stop,” Waters said.

Most of the salt flats are on federal land administered by the Bureau of Land Management, which has been studying the salt loss since it was first detected.

Scientists offered two theories. One held that construction of Interstate 80 across the flats in the 1970s altered the flow of briny surface and ground water that deposits new layers of salt on the flats during the winter.

Another blamed nearly a century of diversion of that brine into huge evaporation ponds where potash used in fertilizer is separated from the salty ooze. The process removes enough salt each year to cover 800 acres one foot deep, a BLM study says.

But the mystery of the missing salt was little known beyond a small circle of geologists and the salt flat racers.

“Nobody else really cared,” said Rick Vescoe, president of the Utah Salt Flats Racing Assn. “There’s nothing green out here and there’s nothing alive.”

Vescoe knows the flats well. As a toddler, he built castles of salt while his father blazed down the track in a ‘40s speedster. His own children are the third generation to challenge speed on the salt.

While BLM scientists were cautious about assigning blame, Vescoe and others in a loose coalition called Save the Salt were not.

“It’s all over there,” Vescoe said, gesturing toward the southern edge of the salt flats and Reilly Industries, an Indianapolis-based chemical company that bought the potash mining operation in 1988.

Clarence Prentice, Reilly’s chief engineer, said his company didn’t know about the problem when it bought the mine--and inherited angry racers who were threatening a lawsuit to force the mine to close.

In 1991, Reilly and the racers jointly persuaded Congress to finance a $1.5-million study of the salt loss. Preliminary results show that Vescoe is right.

U.S. Geological Survey scientist Jim Mason recently reported that salt mining is a “significant contributing factor in the salt depletion.” That single sentence ended a decade-old squabble over who is responsible, and set in motion Reilly’s attempt to reverse the damage.

“We do have excess salt and we might as well put it back out there,” Prentice explained.

The company’s mining process diverts brine from the salt flats into giant ponds, where the sun evaporates the water, separating desirable chemicals from the salt. While gold to the racers, the salt is worthless to Reilly Industries.

Over the coming year, the company will spend $600,000 to build and operate a system of wells, canals, pipes and giant electric pumps that will draw brackish ground water from a distant mountain range, flush it through the settling ponds and squirt the brine back onto the salt flats at a rate of 6,000 gallons per minute. That’s enough salt to cover 28 square miles a half an inch deep each year.

But no one is certain the effort can replicate nature. Some scientists fear that the potash-free salt from Reilly’s ponds won’t bond with the natural salt on the flats, making the surface too mushy for racing. Others worry that the effort will be wasted if the USGS is wrong and some other phenomenon is causing the salt decay.

Still, the racers see the effort as their only hope. “We don’t know if pumping salt will work, but it’s worth a try,” said Mary West, who set women’s land-speed records during the ‘50s and is secretary of Save the Salt. “If it doesn’t, we may lose the salt flats.”