Moreover, the incident highlights vulnerabilities in the screening of cargo that is loaded onto passenger flights, air cargo experts say.
Air-freight shipped aboard windowless aircraft by carriers such as DHL, UPS, and Fed Ex is screened mostly by the companies themselves, experts say. By contrast, all air-freight destined for the cargo hold of a passenger flight destined for or originating in the US is screened by the Transporation Security Administration (TSA).
It's a critical distinction.
"One of the things this definitely shows is the need for more and more robust intelligence both here and overseas," Dr. Henry says. "No system is going to be 100 percent effective - that's why we have to have a layered defense – because something will always slip through one layer or the other."
Cargo carriers responsible for screening
Cargo carriers are clearly interested in catching explosive materials before they get on a plane, he says.
"They understand that a slip up on their end is liable to destroy their business," says Henry. “At same time, they have a business to run and many of the regulations coming down from the government seem to them over the top, bureuacratic and just adding expense."
While TSA says it requires 100 percent of "high-risk cargo" on cargo-only flights to undergo security screening – and has increased the security requirements for such cargo – not all such cargo is screened.
That remains a goal, said TSA Administrator John Pistole in a statement last month. “TSA continues to work closely with our international partners and is making substantial progress toward meeting the 100 percent mark in the next few years.”
Meanwhile, the TSA’s program for screening 100 percent of cargo on passenger flights – mandated by Congress in 2007 and put in force in August – has met with some criticism.
Mr. Pistole called it “another step forward in strengthening the security of air travel.” But an audit by Richard Skinner, inspector general of the Department of Homeland Security, identified "several vulnerabilities with air cargo security.”
These included “access controls to cargo holding areas and background checks for individuals handling air cargo."
In another report last year, the DHS Office of Inspector General found that 23 percent of drivers "did not satisfy the required training and testing requirements.”
Report cites vulnerabilities
The report added that the agency’s cargo inspection process “has not been effective in ensuring that requirements for securing air cargo during ground transportation are understood or followed. The inspection process has focused on quantity rather than outcomes and ensuring corrective actions."
Problems, it said, included inadequate automated tools to help inspectors analyze results and focus their attention on high-risk areas in air cargo security.
The result: "Air cargo is vulnerable to the introduction of explosives and other destructive items before it is loaded onto planes, potentially creating risks for the traveling public," the report stated.
TSA officials responded to that report last year by saying they were responding to suggestions and taking all necessary steps.
Despite the new discovery of bomb material on all-cargo flights, the focus should remain on screening cargo on air-passenger flights, some experts say. They worry that this episode could result in valuable TSA resources being refocused on cargo-only flights, which would water down protection for passenger flights.
"No one is saying these cargo aircraft were the targets," says one air cargo expert who asked not to be named. "Detecting this material is the customs department's responsibility – it's not the TSA's job. It's their job to protect airliners."