(WASHINGTON) -- Ten years after the Sept. 11, 2001 terror attacks, the 9/11 Commission report card on making this country safer from terrorist attacks revealed that U.S. security scored very few A's, lots of C's and incompletes, and at least two significant F's.
Despite billions of dollars spent on aviation security, the report found the U.S. still cannot reliably detect explosives that could bring down a plane.
"We are still highly vulnerable to aviation security threats," said the report, released Wednesday by the Bipartisan Policy Center.
The failure to detect explosives is one of nine unfinished recommendations the 9/11 Commission cited in the report card.
"We really have not gotten it right yet," said Gov. Tom Kean, the co-chairman of the 9/11 Commission which was organized to recommend ways to prevent another terror attack. "Some of these recommendations, no question you get an F."
The Transportation Security Administration acknowledged there is no silver bullet or perfect technology. The agency's former administrator, Kip Hawley, said that by inspecting passengers' shoes and restricting the amount of liquid brought on board, the size of any potential bomb would not be big enough to bring down a plane.
"Yes, you don't want a bomb going off and injuring people on a plane, but you do not want to let them bring on a bomb that will catastrophically destroy the plane," Hawley said.
In response to the report, the TSA said that explosives detection technology was a "key part of a layered approach to aviation security" that has made American travelers safer since the deadly attacks.
"As we approach the tenth anniversary of 9/11, there is no question that America's transportation systems are stronger and more secure than they were a decade ago," TSA spokesperson Greg Soule told ABC News.
Also cited in the commission report card is the failure to remedy the communications breakdown that occurred on Sept. 11 when emergency police and fire units in New York were on different radio frequencies and could not talk to each other.
"People died because of that," said Kean, who now co-chairs the Bipartisan Policy Center's National Security Preparedness Group.
Kean said that Congress was to blame for that shortcoming for failing to allocate new broadcast frequencies for common use by all first responders.
"That should have been done yesterday, and everyday it's not done the American people are less safe," he said.
The report card does praise the work of the FBI and the CIA for finally working together, which it says led to the disruption of many plots and the capture or killing of terrorist operatives.
While security experts said a terror plot precisely similar to the Sept. 11 hijacking plot is highly unlikely, the threat has evolved and there still remain huge vulnerabilities ten years later.
Soule said the TSA stands ready "to confront evolving threats."
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