CONCORD, N.H. (AP) — Standing on the 98-year-old Sewalls Falls Bridge, U.S. Rep. Annie Kuster gestured to the sharp curve leading up to the single-lane span across the Merrimack River.

"How is this even safe at night?" she asked city officials.

Local drivers know to be careful, they told her. But more importantly, they said the deteriorating bridge is a public safety hazard, and not just at night.

In light of the collapse of a Washington state bridge in May, The Associated Press reviewed national bridge records to determine how many fall into two negative categories: bridges that are "fracture critical" because they lack redundant protections and are at risk of collapse if a single, vital component fails; and those that are "structurally deficient" and in need of repair or replacement because at least one major component has advanced deterioration or other problems.

Federal records put 23 of New Hampshire's 2,493 bridges in both categories, though one bridge on the list — the bridge to the Portsmouth Naval Shipyard — is in Maine. Most are in the process of being repaired while others are subject to reduced weight limits or have been closed, according to state officials.

The weight limit on the Sewalls Falls Bridge has been reduced to 3 tons, making it unusable by fire trucks and ambulances. About $12 million in federal, state and city funding has been secured for replacement, but the city needs federal permission to tear it down because it is considered a historic structure. When Kuster toured the bridge Friday with U.S. Sen. Jeanne Shaheen, city engineer Ed Roberge pointed out spots where steel has rotted away and railings have been bent by car crashes. Damage to one major support piece could collapse the entire bridge, he said, sending gas and sewer lines that run along the span into the river.

"This is an example of why we've got to look at investment in infrastructure in the state and the country," said Shaheen.

The Associated Press review of national bridge records found 65,605 structurally deficient bridges and 20,808 fracture critical bridges, according to the most recently available federal data. Some 7,795 bridges fall into both categories.

Among New Hampshire's bridges on the lists, 10 are steel truss bridges and 12 are steel girder bridges with floor beams, according to the state Department of Transportation. Their average age is 79 years, but when more recent repair or rebuilding dates are taken into account, the average age drops to 56 years. Nine are owned by the state; the rest are owned by the towns or cities where they're located.

Six of the bridges are closed, and the allowable weight on five others has been reduced. In most of the other cases, efforts to rehabilitate or replace the bridges are under way, though several are still in the design phase.

David Powelson, chief of the state's bureau of bridge design, said the state does regular bridge inspections, recommends weight limit restrictions for any bridge officials do not think is safe for legal loads and recommends closure for any bridge that cannot safely sustain a three-ton vehicle.