WILMINGTON, Del. — Delaware's transportation secretary ordered immediate inspections of major bridges in the state on Thursday to see if they might have any problems similar to an interstate bypass that had to close in Wilmington.
Meanwhile, the extent of the damage that thousands of cars whizzed past daily before officials realized the bridge was tilting became clear: One of the concrete barriers separating the northbound and southbound lanes popped up 18 inches higher than the other. They are supposed to be the same height.
"This is unbelievable," Delaware Gov. Jack Markell said during a tour of the Interstate 495 span, a critical bypass along I-95.
The bridge, which typically carries about 90,000 vehicles daily, has been closed since Monday, snarling traffic on the crucial north-south artery. It will be weeks, perhaps longer, before it reopens.
The federal government authorized an initial $2 million for repairs and pledged to pick up 90 percent of the total tab because the bridge is part of an interstate. The total cost of repairs is not yet known.
Officials suspect that a large mound of dirt dumped next to the bridge over several years shifted the ground underneath the span and caused the columns to tilt.
Delaware Department of Transportation Secretary Shailen Bhatt said at least part of the pile was on the state's property and a fence that had cordoned off the government's land had been removed.
Bhatt said his agency was checking under major bridges to make sure the state's property is properly marked.
"I want eyes on all those bridges immediately," he told The Associated Press.
In all, there are 1,600 bridges in Delaware, including 91 that are on interstate highways. Bhatt couldn't immediately say exactly how many bridges would be inspected or how long it would take.
The disappearance of the fence exposed a possible gap in the state's inspection program, he said.
Bhatt said he doesn't know what happened to the fence. The agency so far has not contacted law enforcement.
The Federal Highway Administration does not ask states to examine government property around bridges as part of its guidelines for inspections every two years, an agency spokesman said.
Transportation officials from more than a dozen states told AP that they did not plan any special inspections in light of the Delaware trouble. A few states — including Illinois, Mississippi and Tennessee — said they already went beyond the federal guidelines and routinely inspected the land underneath bridges.
Tripp Shenton, who chairs the Department of Civil and Environmental Engineering at the University of Delaware, said that while it's rare for bridges to be damaged by debris on the ground, inspectors probably should be instructed to note anything unusual. In 1996, a large pile of tires caught fire beneath a bridge on I-95 in Philadelphia, damaging the span and closing it briefly.
The governor praised the engineer who first reported the potential problem to state officials last week. The engineer, an employee of a private company on the site for an unrelated project, saw cracking in the soil around the dirt pile and then spotted the leaning columns.
"He was highly observant that something didn't look quite right," Markell said.
The contractor who dumped the dirt is working with state officials to remove it. He was allowed to use the site under an arrangement with a company that leases land next to the bridge.
Despite constant activity by dump trucks and backhoes, crews appeared to have made only a dent in removing the mountain of dirt deposited there. They have installed a fence and signs saying, "State Property No Trespassing."
Associated Press writer Ben Nuckols in Washington contributed to this report.