Defects reported in 70,000 US bridges

The death toll from this week's staggering bridge collapse in Minneapolis rose to five yesterday as authorities across the country issued orders for emergency inspections of spans that have already been identified as having structural problems.

Federal officials have admitted that as many as 70,000 bridges across the US had recently been rated "structurally deficient", the same designation given to the span that catastrophically failed during rush hour on Wednesday, sending scores of vehicles and their passengers plummeting 60ft.

In New York City, attention was focused on the Brooklyn Bridge, which recently failed a state safety test. Engineers said the problems were for the moment concentrated on approach ramps from both the Manhattan and Brooklyn sides. A refurbishment of the span is planned for 2010.

The fifth fatality in Minneapolis was confirmed after emergency workers spent all of Thursday extricating the body of a lorry driver from the twisted wreckage of the Interstate 35W bridge. The death toll is expected to rise further with at least eight people still missing. Rescue efforts were being impeded by harsh conditions, with the murky waters of the river filled with dangerous and shifting shafts of concrete and steel.

"Conditions on the river ... are even more treacherous than yesterday. We will be slow and methodical during our search operations today," the local Sheriff, Rich Stanek, warned. In addition to the dead and missing, 79 people were injured.

Concern was mounting that too little has been done to maintain America's vast interstate transport network because of an unwillingness at the federal and state levels to spend enough money. Engineers said it would take a generation, and $188bn (£92bn) just to get all the system's bridges up to standard.

"We're not doing what the engineers are saying we need to be doing," said Gregory Cohen, the president of the American Highway Users Alliance. "Unfortunately when you consistently underinvest in roads and bridges ... this is the dangerous consequence."

Officials in New York rushed to reassure the public that the Brooklyn Bridge, one of only three in the city that has recently been rated in "poor condition", remains safe. "The poor rating for the Brooklyn Bridge means that there's only components of the bridge that are in poor condition," said Lori A Ardito, first deputy commissioner at the city's Department of Transportation.

The governors of numerous states, including New York, reacted to the tragedy by ordering engineers either to re-inspect bridges or re-examine the most recent inspection reports. Scrutiny will be most intense for those of the same design as the Minneapolis bridge.

According to the American Society of Civil Engineers, the US would need to spend $9.4bn annually for the next 20 years to address all the problems with its aging bridges. The 70,000 spans now considered structurally deficient represent 12 per cent of all bridges in the country.