New York:
The discovery of two explosive devices shipped by cargo planes has reignited a long-running debate about how thoroughly cargo needs to be screened on its way into the United States.
Despite the increased scrutiny of people and luggage on passenger planes since 9/11, there are far fewer safeguards for packages and bundles, particularly when loaded on cargo-only planes. The issue has come up in Congress repeatedly and was the subject of a recent report by the research arm of Congress that warned new mandates were not being met.
Industry experts said the latest case suggested that terrorists may have singled out cargo aircraft precisely because they are not subject to the same scrutiny as passenger planes.
Only a small percentage of all cargo from abroad is physically checked on freight planes bound for the United States. A law that took effect in August requiring full screening does not apply.
"The 100 percent screening requirements only pertains to passenger flights that carry air cargo," said Steve Lord, a director of homeland security and justice issues at the Government Accountability Office.
The size of a package can determine whether it is physically checked. A legislative aide who has studied the issue said large packages were subject to a higher level of scrutiny, usually meaning they are opened, in an effort partly meant to detect stowaways. If a package makes an official suspicious, for instance if it is leaking or has protruding wires, it will be inspected, industry sources said. Sometimes, cargo on freight planes is tracked by only packing lists or manifests.
All cargo on passenger planes, on the other hand, which carry about 16 percent of all cargo that comes into, leaves and travels within the United States, are bound by the August law to have physical inspections using technology and other means. Those screening measures are conducted by private contractors, officials of a foreign government or by American customs officials in some countries.
In addition, planes carrying only freight that are scheduled to transfer to a passenger flight are subject to the full screening law. But as the G.A.O. noted in a June 2010 report, the federal government has yet to meet these requirements for inbound air cargo on passenger flights.
"Even though it is subject to the law, it is not yet being screened 100 percent," Mr. Lord said. "T.S.A. is still devising a system to screen this cargo. That is a potential vulnerability."
In a statement, the transportation administration said that it screens 100 percent of all cargo on domestic flights as well as 100 percent of what it described as "high-risk" international inbound air cargo packages on passenger planes. However, a T.S.A. official declined to say what percentage of cargo on international cargo flights is screened.
Representative Edward Markey, a Massachusetts Democrat who was an author of the August law, said, "Given the terrorist threats that we face, the need for continued vigilance is clear when it comes to cargo on aircraft."
Over all, 20 million pounds of cargo is transported on domestic and inbound passenger aircraft daily.
Officials of both FedEx and United Parcel Service declined to provide details about their screening practices but said their procedures exceeded federal regulations. Both carriers said that they rely on contract carriers in Yemen and do not fly their own planes there. On Friday, the companies said that they had embargoed shipments from Yemen or suspended service from that country.
The suspicious package intercepted in England was shipped through United Parcel Service. Karen Cole, a spokeswoman for the company, declined to say whether a company plane carried that package at any point in its route.
Maury S. Lane, a spokesman for FedEx, said the carrier learned that a suspect package might be at its Dubai facility when it was contacted by the F.B.I. and local authorities in Dubai. "We were contacted, and the package was intercepted shortly afterwards," Mr. Lane said.
Michael D. Whatley, a partner at HBW Resources, which is a consulting firm for the Air Cargo Security Alliance, an organization that represents the cargo airlines, said that there is no way to force American standards on other countries loading cargo bound for the United States.
"That is a huge hole," said Mr. Whatley. "So we have to rely on international treaties and bilateral negotiations and all the different tools that we have as a country to get the other countries to do it on their territory."
Aviation officials have been under Congressional pressure for nearly a decade to ensure that air cargo loaded onto passenger planes is checked for possible explosives. Critics have argued it made no sense for the United States to have spent billions of dollars to examine all carry-on bags and checked baggage but allow cargo to be loaded onto passenger planes without scrutiny.
Congress, frustrated with the progress, mandated in 2007 that the Transportation Security Administration take steps to ensure that all air cargo on passenger planes be inspected -- on domestic flights and international flights headed to the United States -- by August 2010. Homeland Security recently acknowledged it would not meet the deadline for international cargo.
Earlier this year, Gale D. Rossides, then acting director of the Transportation Security Administration, , told a House committee that about 80 to 85 percent of international cargo headed for passenger planes would be inspected as of the August deadline, and cited the difficulty of getting certain international airports to comply.
"We're visiting these countries," Ms. Rossides told a House Homeland Security subcommittee in June. "We're giving them our standards. We're assisting them with teams of T.S.A. experts."
The G.A.O. audit said that part of the problem is that the Transportation Security Administration as of earlier this year had not approved the use of devices to screen large pallets or containers of cargo. A significant amount of air cargo headed to the United States is also given an exemption from screening if it is in shrink-wrapped bundles, based on an assumption that the shipper knows the contents are secure, the audit said.
Perhaps more troubling, the audit found that the agency could not say for sure that air carriers are complying with the mandates to screen cargo even at airports where the system is supposedly in place. The inspections are done by private companies, not government security officers, and the federal government does not have a reliable way to monitor the process.