Fear of Fire, Flood Keeps St. Louis Jittery : Disaster: Flood wall seepage poses threat to a 25-mile-long industrial area. Homes face peril from 51 propane tanks floating on the Mississippi.

With the potential for twin disasters at hand, this city of 400,000 and its environs suffered a legitimate case of the jitters Monday as the great flood of 1993 continued besieging the region.

The Mississippi River infiltrated the ground behind the St. Louis flood wall, sending its murky waters bubbling up through manhole covers, spurting out of engineers’ measurement wells and seeping up to form a swamp complete with quicksand.

If the flood wall fails, an industrial area 25 miles long and a quarter-mile wide could be submerged.

On the south side, more than 1.5 million gallons of volatile propane remained in 51 tanks only loosely attached to moorings in the rising and falling floodwaters. If propane vapor escapes and ignites, the result could be a fireball that blows out brick walls a mile away and breaks windows two miles away.

Police and National Guard troops rapped on doors in the early morning to order thousands more residents out of their homes near the tanks, bringing the total evacuated on the Missouri side to 9,000. Some precautionary evacuations were also ordered across the river at East Carondelet, Ill.

The cresting Mississippi, fed by the swollen Missouri and Illinois rivers, continued to perplex the experts. And it deluged still more territory.

Officials at the U.S. Army Corps of Engineers wondered if the actual maximum height had come about 9 p.m. on Sunday, at a mere 48.7 feet--nearly 19 feet above flood stage. It was a monstrous size, but lower than the 50- or 51-foot crest they had feared. They thought that the levees that had toppled earlier in the day might have spread out enough water to relieve the pressure.

But no one was willing to say so flat-out. The saga of the Midwest floods has had as many strange twists as the rivers now overflowing their banks, and definitive statements are no longer considered wise.

The destruction continued downstream as the high water rolled on, with the Harrisonville Levee folding shortly after dawn. The Mississippi won 46,000 acres there. Most of the land was farm fields, but Valmeyer, Ill.--once population 900, now population 0--also was inundated.

Corps officials were flying helicopter surveys over the last two remaining levees on the Missouri east of Kansas City. The Riverport and Earth City dikes stand side-by-side across from flooded St. Charles, protecting hundreds of millions of dollars worth of offices and hotels.

So far the Flood of ’93 has caused at least $10 billion in damage and claimed 46 lives, the latest the body of a woman discovered in North Dakota.

On a platform atop the St. Louis flood wall, the scope of the battle was clear. On the river side, the caramel-colored Mississippi flowed just five feet below, past the tips of high cottonwood trees.

On the city side, work crews 14 feet further down unfurled sheets of black plastic while dump trucks prepared to drop tons of limestone chunks on sinkholes and quicksand and sand boils. Twice already this day, Corps engineer Len Ross had sunk to his knees in the muck.

The river was making incursions and if allowed to continue unchecked, the dike’s foundation would wash away, the flood wall would tip forward and the waters would rush over railroad tracks, factories and sewage treatment plants.

This was the worst spot along the 11-mile defense system. Just to the south, a well sunk to measure the pressure of the underground water sent a geyser spurting six feet into the air.

On Monday the leaks, seeps and sprays were showing up all along the levee.

“I’m trained in this,” Ross said. “And I am not comfortable. This is a very, very serious situation.”

And it will not go away with the crest--the water will stay high for months. “There’s a big difference between a levee and a dam,” Ross said. “Dams were built to hold this kind of water off forever. A levee is for quick up-and-down. We can’t afford to build a dam here.”

A dozen divers, working in teams of four, resumed efforts to slowly drain gas from the pipes connecting 51 precariously balanced tanks, each containing 30,000 gallons of propane, at the Phillips Pipe Line Co.

Officials hope that such action will help keep the tanks themselves in place. The rising river has loosened straps binding the tanks to concrete saddles; they are now held only by the three-inch pipes.

The delicate process had been suspended after two clouds of escaping vapor flamed briefly.

The fires helped persuade authorities that the evacuation area had to be widened. “Propane is a nasty little devil. It always finds a source of ignition somewhere,” said St. Louis Fire Chief Neil Svetanics.

Early in the morning, the 900 residents of Valmeyer were sandbagging desperately. Then the Mississippi rose so high it simply flowed right over the barrier.

By noon, the gas station was gone. The interior decorating shop--gone. The mural, depicting Valmeyer’s history that the kids recently finished painting at the school library--gone, too.

Another day will pass before the last house goes under, but go under it is expected to.

And just as surely, Mayor Dennis Knobloch vowed, Valmeyer will rebuild. “We will come back,” he said. “But when?”

Times staff writer Melissa Healy contributed to this story from Washington.

Fears of a Fireball

Thousands of residents were evacuated south of St. Louis for fear that floating tanks of propane might explode. Meanwhile, the Mississippi apparently has struck its worst blow to St. Louis and rolled on.

Riverport and Earth City: Last unbreached levees on Missouri.

Alton: 70,000 without drinking water.

St. Louis: River levels begin to drop.

River Des Peres: Propane tanks force evacuation.

East Carondelet: Also evacuated