FRANKFURT, Germany: The head of the International Air Transport Association urged governments and industry on Tuesday to rapidly develop effective equipment such as oversized X-ray machines to screen the cargo containers that carry most airborne freight. Giovanni Bisignani spoke several days after two explosive devices were discovered concealed aboard freight being carried by cargo jets bound for the United States. Bisignani said the technology for such security equipment already exists, but that it is taking too long to approve it for airport use. “There is no technology today that governments have certified to screen standard size pallets and large items,” Bisignani told the association's regularly scheduled meeting on the security of passenger and cargo planes. “There is some promising technology, but it is taking far too long to move from the laboratory to the airport. We must speed up the process.” US Transportation Security Administration chief John Pistole, who also attended the conference, said a delicate balance needs to be struck to ensure that the enhanced security requirements for airfreight do not disrupt global trade. “The flow of global commerce is key to economic recovery,” Pistole said. “Security cannot bring business to a standstill.” He said aviation security was a shared responsibility because the latest events showed that “threats evolve as quickly as we can develop mitigation measures.” “This latest plot highlighted two points,” Pistole said. “One that we face a determined and creative enemy with innovative design and concealment of IEDs (improvised explosive devices).” “And second that we have a critical need for global interdependence in aviation security.” Air freight is often transported in containers that generally are not taken apart to inspect because the process would significantly slow down air travel and the movement of goods. Currently, airports rely on dogs, trace detection, and visual inspections to check most air cargo containers without having to open them. Screening technology to handle large containers _ similar to the passenger X-ray machines in general use _ is being tested. The International Air Transport Association did not estimate how many of the new machines will be needed to check all cargo carried by the world's airlines. A single high-radiation machine would likely cost $5-$6 million, according to manufacturers' estimates. Bisignani urged national governments to shoulder at least a portion of the rapidly expanding costs of aviation security. In Europe this is borne by the airports themselves; in the US it is paid for by the federal government. “I don't understand why security at a football stadium is the government's responsibility, but aviation security is not,” he said, adding that last year airlines around the world paid a total of $5.9 billion for security. Last week, two explosive devices were discovered in Dubai and Britain concealed in freight being carried by cargo jets. Officials have said that without a tip-off from authorities in Saudi Arabia, the bombs may not have been discovered. Both mail bombs were wired to detonators that used cell phone technology. The International Air Transport Association is promoting a plan to monitor and speed up the movement of all air freight through the use of a single e-freight tag that would do away with the dozens of papers accompanying each freight container by replacing them with a single document similar to the e-tickets used by the vast majority of airline passengers nowadays. “We believe it is now time to abolish paper from the cargo system ... just as e-tickets replaced the millions of paper tickets,” Bisignani said, adding that the new system would “allow us to manage cargo security intelligently and efficiently without compromising on speed.”