Meanwhile a new controversy has arisen at Ground Zero.
A collection of expert analysis and data that could help explain how and why the World Trade Center collapsed has reportedly been compiled as part of an insurance lawsuit in Manhattan, but the public may never see the information.
According to The New York Times, the experts who amassed the information are forbidden by confidential agreements from discussing their findings. The material could be withheld if the lawsuit is settled before trial, prompting concern among engineers and victims' families that the confidential material may be sealed or even destroyed.
"We're obviously in favor of releasing the information, but we can't until we're told what to do," said Matthys Levy, an engineer and consultant in the case.
The Times says the material contains documentary evidence, including maps of the debris piles, as well as three-dimensional computerized images of the fallen towers. Rare photos and videos also have been collected.
The information was gathered - largely in secret - as part of a lawsuit involving a group of insurance companies and Larry Silverstein, the leaseholder of the trade center property. The insurance companies say the hijackings constituted a single terrorist attack, while Silverstein maintains that the two planes hit the twin towers in separate occurrences.
Silverstein believes he's entitled to a $7 billion payment; the insurance companies say he should be paid half that amount.
Silverstein and the insurers have spent hundreds and thousands of dollars seeking expert analysis about what caused the collapse.
The Port Authority of New York and New Jersey, which owned the Trade Center complex, said in a statement that access to documents would be decided on a "case-by-case basis consistent with applicable law and policy."