Tuesday, November 9, 2010

Canine Remote Explosive Scent Tracing, Long Used in Europe for Screening Air Cargo, Continues to Be Tested in U.S.

Federal law mandates searching checked luggage, which may be done by canine teams, certain equipment, and other means, but luggage is not the only thing that goes into the hold of a plane. Air cargo also goes there. As recent events have made clear, cargo may not be screened as effectively as luggage. Although Congressional and Administrative policy has been to increase the number of explosives detection canine teams at U.S. airports, one of the more sophisticated explosives detection approaches awaits implementation in the U.S. despite widespread use in Europe.

A landmine detection methodology first developed in South Africa in 1985 (see blog of May 29, 2009) has in the last decade been adapted to sample air cargo for explosives. This method, called remote explosive scent tracing (REST) or sometimes remote air sampling for canine olfaction (RASCO), involves using dogs to sniff air samples at stations that are located in sterile rooms, much like those used in advanced scent identification procedures. The samples are extracted from cargo containers, or from under the plastic wrapping that holds a large number of packages together for shipment, using a suction device so that the sample presented to the dog comes from a confined airspace. An alert by a dog has a high probability of identifying the presence of an explosive among the items within the confined airspace.

Dogs are not the only animals used in REST work. One organization involved in removing landmines in Tanzania and Mozambique has had considerable success with rats.

Remote explosive detection is particularly useful with cargo because of the fact that unbundling materials being shipped together is both expensive and time consuming, and in some cases, such as with pharmaceuticals, can damage or destroy a shipment. About 12% of air cargo in the U.S. travels on passenger planes, but about 16% of air cargo coming into the U.S. reportedly comes on passenger planes. Air cargo operators in the U.S., such as FedEx and UPS, tend to have dedicated cargo fleets, and some passenger airlines, such as Northwest and United, also have dedicated cargo fleets. Overseas, about 22% of air cargo travels on passenger planes. It thus appears that over 80% of air cargo in the U.S. is not subject to the screening requirements that apply to cargo placed in the holds of passenger planes, even assuming the latter requirements are consistently met.

Use of REST in Europe

In 2004, a commercial system began to be used by agencies of the governments of France, and the UK approved it for screening cargo. The Netherlands Ministry of Justice and Military Police approved it in 2006. (See written question of Jeanine Hennis-Plasschaert, a member to the Dutch House of Representatives, to the EC, February 28, 2008.) REST is also used in the Amsterdam Schiphol and Johannesburg airports. The picture (courtesy DiagNose) shows a dog checking stations in a REST system.

In 2007, the Government Accountability Office published a report on aviation security, Federal Efforts to Secure U.S.-bound Air Cargo Are in the Early Stages and Could be Strengthened. The GAO discussed remote scent tracing:

"[T]wo European countries [presumably England and France] are currently using canines in a different manner than TSA to inspect air cargo for explosives. Specifically, these countries are using the Remote Air Sampling for Canine Olfaction (RASCO) technique, which involves the use of highly trained dogs to sniff air samples collected from air cargo or trucks through a specially designed filter. The dogs sniff a series of air samples to determine whether or not there is a trace of explosives and indicate a positive detection by sitting beside the sample. According to foreign government officials representing two of the countries that use this technique, tests to determine the effectiveness of this practice have shown that RASCO has a very high rate of effectiveness in detecting traces of explosives in cargo. According to foreign government officials, this inspection method can be used on cargo that is difficult to inspect using other methods, due to size, density, or clutter, and does not require the breakdown of large cargo pallets. Further, officials stated that the dogs used in RASCO do not tire as easily as dogs involved in searching cargo warehouses, and can therefore be used for a longer period of time…. According to TSA officials, while the results of previous agency tests of RASCO raised questions about its effectiveness, they continue to work with their international counterparts to obtain information on the feasibility of using RASCO to inspect air cargo. TSA officials stated that the agency has not yet determined whether RASCO is sufficiently effective at finding explosive in quantities the could cause catastrophic damage to an aircraft and whether this technique will be approved for use in the United states."

In a 2010 report on air cargo security, the GAO referred to RASCO again, but made no mention of its possible implementation in the U.S. The GAO did state that RASCO might "produce different results from TSA's screening standards," but it is not clear if this was a reference to any research TSA had conducted.

The Scientific Working Group on Dog and Orthogonal detector Guidelines (SWGDOG), which suggests industry standards on the training and uses of police dogs, said in its 2007 Guideline SC7-Research and Technology that independent scientific evaluations of the capabilities and limitations of the REST systems are essential. A 2010 proposed revision includes the same urgent recommendation. In Norway, Rune Fjellanger, the preeminent researcher on the method, reported 95% detection reliability eight years ago, thus meeting the U.S. military's standard for explosives detection dogs.

How Effectively Is Air Cargo Screened Before Going on Passenger Planes?

The bombs hidden in printer cartridges found at airports in East Midlands and Dubai last week contained PETN (pentaerythritol tetranitrate). East Midlands Airport is the UK’s busiest pure cargo airport, handling 300,000 tons of flown cargo every year. It is the UK hub for DHL and UPS, and it was in a UPS package that the disguised explosive device was found. News reports stated that the bombs had been on passenger planes during their journeys.

The Implementing Recommendations of the 9/11 Commission Act of 2007 (PL 110-53, August 3, 2007) contained provisions (§ 1602) on the screening of cargo carried aboard passenger aircraft, which required that, by August 2010, “the Secretary of Homeland Security shall establish a system to screen 100 percent of cargo transported on passenger aircraft operated by an air carrier or foreign air carrier in air transportation or intrastate air transportation to ensure the security of all such passenger aircraft carrying cargo.” Screening may include various technologies including “explosives detection canine teams certified by the Transportation Security Administration.” The Act also encouraged the use of blast-resistant cargo containers (§ 1609).

In 2008, the GAO reported that there were 370 TSA-certified explosives detection canine teams cross-trained to work in multiple aviation environments, including air cargo. Teams specializing in air cargo were located primarily at the 20 airports that receive approximately 65% of the air cargo transported in the U.S. In June 2010, the Transportation Security Administration issued a statement, 100% Air Cargo Screening: Path Forward, admitting that “screening 100 percent of cargo inbound to the US will not be attainable by industry by the August [2010] deadline, however TSA is committed to ensuring industry obtain that level of security as rapidly as possible.”

A Report to Congress in 2007 noted that it was not only the amount of cargo that was shipped on passenger airlines that was a problem for screening everything, it was also the complexity of the system. About 50 air carriers transport air cargo on passenger airlines from nearly two million shippers every day. Approximately 80% of the shippers use freight forwarders who operate about 10,000 facilities in the U.S. The TSA has, therefore, relied on a strategy of establishing databases of known shippers and freight forwarders and comparing shipments to entities labeled as approved in databases. When a match is not found, a targeted inspection can be initiated. The report stated that TSA policy is to “screen, inspect, or otherwise ensure the security of all-cargo aircraft is to be established as soon as practicable, but sets no specific deadlines or time frame for compliance.” When air cargo arrives in the U.S. from abroad and is transferred to a domestic passenger flight, TSA's policy is that this cargo "must be made available to TSA canine teams when these teams are present in cargo facilities."

At present, when canine teams inspect cargo, the procedure primarily involves running a dog through a loading area or having it stand beside a conveyer belt where it sniffs the packages as they pass. One bomb dog handler advised me that sometimes air cargo facilities are concerned about a shipment wrapped in plastic but do not want the wrapping unbundled, so he slits the package on each side allowing the dog to sniff the air inside the wrapping. He acknowledged that a remote air scenting system would have been preferable.

In a 2009 report reviewing TSA’s progress in screening, the GAO said that there were only 37 canine teams dedicated to air cargo screening, but added that there would soon be 48 more, meaning that there are now somewhere around 100 dedicated air cargo sniffing dogs. The report said that TSA was attempting to identify peak cargo delivery times during which dogs would be most helpful for screening. This suggests that packages arriving at non-peak times may not be screened.

EU Requirements

The European Commission provides standards for aviation security in the EU. After April 2009, European Commission Regulation 272/2009 allows screening of passengers and employees at checkpoints to be performed by dogs, as well as cabin baggage and baggage carried at a checkpoint, hold luggage and other cargo and mail to be loaded into the hold. Vehicles and the aircraft themselves may also be searched by explosive detection dogs.

In Regulation 573/2010, the Commission elaborated considerably on explosive detection dog requirements. Dogs are to be single purpose dogs and are to be taught to give a passive response. The EDD and the handler must both be approved independently and in combination. Both are to receive initial and recurrent training. Recurrent training is to occur at intervals of no longer than six weeks. Recurrent training sessions are to be at least four hours long. Training records are to be kept on both the EDD and the handler. Finally, the Regulation provides that security screening may involve free running or remote explosive scent tracing. REST may also be used for screening cabin and carry-on baggage, vehicles, aircraft, in-flight supplies and airport supplies. Dogs used in REST work can have two handlers, presumably a recognition that dogs can do this work for longer periods than is the case in traditional sniffing assignments.

Where Does TSA Stand on Implementing REST?

A 2008 Report to Congress stated that TSA was working with the Department of Homeland Security on operational procedures to improve canine detection capabilities. The Report stated: "One technology being examined is Remote Air Sampling Canine Olfaction (RASCO) sensors, which can provide a concentrated sample from a container for a canine to inspect and has been used extensively in Europe. The DHS project plans to expand this concept to include chemical sensors carried on jackets worn by the canine that will be capable of transmitting data to remote monitoring stations."

Perhaps TSA's efforts to combine the dog's sniff with a chemical sniff explains the delay in implementing REST in the U.S.

The Technical Support Working Group, an interagency program for research and development into counter-terrorism measures, has posted a Combating Terrorism Technical Support Office 2009 Review. A section of the Review on "next-generation canines" indicates that TSWG is exploring "technologies that support and enhance canine detection." TSWG is under the Combating Terrorism Technical Support Office (CTTSO), which is under the Assistant Secretary of Defense for Special Operations/Low-Intensity Conflict & Independent Capabilities. Proposals for RASCO testing were invited by CTTSO in October 2008 (Broad Agency Announcement 09-Q-4500). The following describes the tests that were sought:

"The performing organization will be required to design, develop and operate a RASCO test-bed for air cargo screening. This test-bed shall be a model of activities of an air-cargo facility which has deployed the RASCO screening process. A warehouse where cargo can be assembled into air shipping configurations and then arranged for sampling will be required. The warehouse shall also have a separate area for canine interrogation of the samples. The test-bed shall have separate storage areas for used and unused commodities and shall have storage facilities for bulk amounts of explosives. The investigating entity shall be fully licensed to receive, store, handle and ship bulk explosives. (This can happen up to two months after award if necessary). The site shall have the capability to accept and ship large amounts of air cargo commodities in their shipping configuration or broken down as required. The contractor shall have knowledge of U.S. air cargo screening requirements. The contractor shall procure and train canines to detect trace amounts of explosives using a government furnished protocol. Canines must be maintained for long periods of time at a location remote from explosive storage. It is noted that the training procedures for RASCO may not be the same as for other types of canine detection. These training procedures will be provided by the government. The training aids [generally samples of explosives] used shall be fabricated by the performer using established procedures. Adequate facilities shall be available for the formulation of training aids. The procedures for fabrication will be supplied by the government. The option to use the test-bed as a permanent facility for training and testing is desirable. Authentic air cargo samples must be taken and used for training purposes. The awardee must be able to supply these samples to the test-bed. A location near an air cargo hub is desirable."

It would seem then that testing is going on, and may have been going on for several years.

Update Note:  In testimony before Congress in 2014, TSA officials stated:

"Recommendations of the 9/11 Commission Act of 2007 directed DHS to examine the use of third party explosive detection canine teams for air cargo screening. In 2011, TSA, in coordination with the DHS Science and Technology Directorate (S&T), conducted a Third Party Pilot Assessment to examine the use of these teams in the cargo environment. TSA and DHS S&T analyzed current industry detection canine capabilities through a pilot to determine the degree of modification to industry programs needed to adopt and implement TSA screening standards. The assessment revealed inconsistent results of industry programs due to unsatisfactory odor recognition and performance. However, TSA remains open to future proposals on third party canine use."


It is unlikely that the Transportation Security Administration would make a public statement regarding a specific commercial provider, but it should acknowledge the existence of the approach and place it in an advisory, if not a regulatory, context. REST has been tested by various countries and at various cargo facilities, both air and maritime (as well as for downloading air samples from trucks in some locations), and the risks associated with air and marine cargo argue for implementation as soon as is practicable.

Additional Sources: Fjellanger, R., Andersen, E.K., and McLean, I.G. (2002). A Training Program for Filter-Search Mine Detection Dogs. International Journal of Comparative Psychology, 15, 277-286. Fjellanger, R. (2002) REST—A Method for Detection of Explosive and Chemical Substances. Abstract in Proceedings, Vapor and Trace Detection of Explosives for Anti-Terrorism Purposes, Technological Centre, Russia. Uddqvist, A. and Roberthson, I. (2010). Improvement of Sampling System for Remote Explosive Scent Tracing. Bachelor’s Degree Project in Mechanical Engineering, University of Skovde, Sweden, Spring 2010. See also Fjellanger’s website; Meier, B. and Lipton, E. (2010). In Air Cargo Business, It’s Speed vs. Screening, Creating a Weak Link in Security. New York Times, November 2, A12 (citing the International Air Cargo Association that 16% of cargo carried into the U.S. comes on passenger planes); ICTS Europe Q1 Newsletter 2010 (canine trials at central search areas of East Midlands and other UK airports, indicating full implementation had not been approved); Elias, B., CRS Report for Congress: Air Cargo Security (updated July 30, 2007);TSA Air Cargo Programs Update (FY 2008 Q2) (showing that only 12% of U.S. air cargo goes by passenger aircraft. This was the TSA Air Cargo Programs Update describing the Certified Cargo Screening Program (CCSP)); Statement of Inspector General Kenneth M. Mead, DOT, Key Issues Concerning Implementation of the Aviation and Transportation Security Act, Report CC-2002-098 (February 5, 2002); Wickens, B. (2001). Remote Air Sampling for Canine Olfaction. IEEE 35th International Carnahan Conference on Security Technology, 100-102.

Addendum. I thank readers for sending me comments and additional leads regarding this subject since I first posted the blog two days ago. Perhaps the biggest advantage of an increased readership is that people are happy to point out errors and oversights. Even before I opened the New York Times this morning (November 11), I was directed to the story John Burns on A6, Yemen Bomb Could Have Gone Off at East Coast, stating that the package in Britain had been missed by sniffer dogs and explosives-detection equipment. I have been advised that there is no REST system at the East Midlands cargo facility, so if this is where dogs did not alert to the package, they must have been taken past it by a handler.

Second Addendum. Steve Lord, Director of Homeland Security and Justice Issues with the Government Accountability Office, testifying before the Subcommittee on Transportation Security of the House Committee on Homeland Security, on March 9, said that the Transportation Security Administration had, as of February 2011, 113 dedicated air cargo screening teams working at 20 airports, but would be adding seven additional teams. He also stated that a pilot program at two certified cargo screening facilities (CCSFs) was testing the feasibility of using private canine teams to inspect air cargo. Certain air cargo is not screened by dogs, however, as is made clear from the following portion of Lord's statement:

"TSA has not approved or qualified any equipment to screen cargo transported on unit-load device (ULD) pallets or containers—both of which are common means of transporting air cargo on wide-body passenger aircraft—both domestic and inbound aircraft. Cargo transported on wide-body passenger aircraft makes up 76 percent of domestic air cargo shipments transported on passenger aircraft. The maximum size cargo configuration that may be screened is a 48-by-48-by-65-inch skid—much smaller than the large pallets that are typically transported on wide-body passenger aircraft. Prior to May 1, 2010, canine screening was the only screening method, other than physical search, approved by TSA to screen such cargo configurations. However, effective May 1, 2010, the agency no longer allows canine teams to screen ULD pallets and containers given TSA concerns about the effectiveness of this screening method for those cargo configurations."

Lord states that TSA is continuing to test other screening technologies for ULDs. It appears that cargo may remain the most significant hole in passenger airline security.

On March 14, 2011, DiagNose announced that its trademarked system is now in use at the Amsterdam Schiphol Airport.

Third Addendum. Attachment 12-H to Regulation 573/2010 specifies size limits for consolidated consignments for explosives detection dog screening. The Attachment reads as follows:

“When screening cargo (including the cargo consignments of express parcels), the consignment shall be made available for screening in a non-containerised packing. The height of consolidated consignments shall not exceed 130 cm in height and 100 cm in depth [just over 4 ft. x 3 ft. 3 in.], unless a single piece of consignment is exceeding such dimensions. The nature of each consignment shall be taken into account before the handler shall direct the EDD to each item and evaluate the reaction of the EDD. The EDD shall be able to access and sample odour from all pieces of cargo.”

This means that if a consolidated consignment can be sniffed from both sides, it can be up to 200 cm wide (about 6½ ft.). For consignments higher than 130 cm, a ramp can be used for the dog to sniff the top of the consignment.

At least one company providing canine services for cargo screening has requested additional guidance from the European Commission. The EU responded that existing EU legislation on explosive detection dogs can only be reviewed after it has been in place for a reasonable period of time, but if other industry stakeholders believed the need to be more urgent, the Directorate General on Mobility and Transport will investigate "at an earlier stage." So far this has not happened.


  1. Dear John,
    This post is very professional (as usual, I must say), indeed the REST method for cargo screening has proven to be very efficient in terms of detection rate and also, very important, a real cost-saving solution.
    If I may, I would like to inform your readers that our company, DiagNose, is providing REST cargo screening services worldwide (we call the system "RASCargO"), in most of the cases we do not charge any setup fees, we charge only for actual screening done.
    We are always happy to cooperate with cargo market stakeholders and to see whether we can build a win-win solution together.

    Thank you for your important work,
    Ido Yitzhaki - DiagNose

  2. this technique failed in Israel several times don't think to work with it, if you want to explore this system just vacuum the explosive and no dog will ever find it , besides test it with several materials conventional and improvised and you will see that this technique doesn't function at all

    1. Mike, Please verify your sources. your post is completely wrong.

  3. Hi Mike,
    I don't know what is the actual basis of your comment but I am sure it is not based on facts or real experience.
    The REST method was tested many times by authorities of at least 8 countries and has proven to be very effective. The EU has recently authorized it as a primary method of cargo screening after 4 years of testing.
    About Israel - the Israelis don't like any system that was not invented there... does this mean that the REST method is non-effective? definitely not. I advise you to check again.

  4. Bullshit ... I am Israeli familiar with the method and more ..
    the Ras Cargo technique give you 0 zero detection on real explosive like TATP
    once the terrorist will realize where the technique is applied there they will attack there

  5. we try this method in our country and ı have to say it works...

  6. Canine Remote Explosive Scent Tracing has gain more recognition since it inspection.

  7. Since november 2014 the UK has banned RESt method because test showed it did not work.
    I must say comparing rat sniffing small area's for landmines with dogs doing complete trucks is a world apart, and I can not believe that people keep mixing these things up.
    There are much different ways of collecting air samples, and I simply do not believe, as is mentioned here above that a dog is capable of sniffing out and IED from a complete truck. Especialy not when freight inside the truck is air sealed.

    1. Its because the protocols imposed by DfT in the UK are obsolete and wrong. so the UK TSA trial failed and REST was then banned. Exactly the same trial carried our in Paris and Amsterdam resulted in TSA recognition. Meaning the system works, but you ned to know how to operate it, and the DfT does not know how. Unfortunately.