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Tuesday, 14 September 2010

Letter bombs - security information and advice

  • Published: Wednesday, 7 February 2007

Letter bombs, which include parcels, packages and anything delivered by post or courier, have been a commonly used terrorist device.

A properly conducted risk assessment should give you a good idea of the likely threat to your organisation and indicate precautions you need to take.

Letter bombs may be explosive or incendiary (the two most likely kinds), or conceivably chemical, biological or radiological. Anyone receiving a suspicious delivery is unlikely to know which type it is, so procedures should cater for every eventuality.

A letter bomb will probably have received fairly rough handling in the post and so is unlikely to detonate through being moved, but any attempt at opening it may set it off. Unless delivered by courier, it is unlikely to contain a timing device.

Letter bombs come in a variety of shapes and sizes; a well-made one will look innocuous but there may be tell-tale signs.

Indicators of a letter bomb

  • it is unexpected or of unusual origin or from an unfamiliar sender
  • there is no return address or the address cannot be verified
  • it is poorly or inaccurately addressed, e.g. incorrect title, spelt wrongly, title but no name or addressed to an individual no longer with the company
  • the address has been printed unevenly or in an unusual way
  • the writing is in an unfamiliar foreign style
  • there are unusual postmarks or postage paid marks
  • a Jiffy bag, or similar padded envelope, has been used
  • it seems unusually heavy for its size. Most letters weigh up to about 30g, whereas most effective letter bombs weigh 50-100g and are 5mm or more thick
  • it has more than the appropriate value of stamps for its size and weight
  • it is marked 'personal' or 'confidential'
  • it is oddly shaped or lopsided
  • the envelope flap is stuck down completely (a normal letter usually has an ungummed gap of 35mm at the corners)
  • there is a pin-sized hole in the envelope or package wrapping
  • there is any unusual smell, including but not restricted to almonds, ammonia or marzipan
  • it has greasy or oily stains on the envelope
  • there is an additional inner envelope and it is tightly taped or tied (however, in some organisations sensitive material is sent in double envelopes as standard procedure).

What you can do

Although any suspect item should be treated seriously, remember that the great majority will be false alarms and a few may be hoaxes. Try to ensure that your procedures, while effective, are not needlessly disruptive. Take the following into account in your planning:

  • seek advice from your local police CTSA on the threat and on defensive measures
  • consider processing all incoming mail and deliveries at one point only. This should ideally be off-site or in a separate building, or at least in an area that can easily be isolated and in which deliveries can be handled without taking them through other parts of the building
  • make sure that all staff who handle mail are briefed and trained. Include reception staff. Encourage regular correspondents to put their return address on each item
  • ensure that all sources of incoming mail (e.g. Royal Mail, couriers, hand delivery) are included in your screening process
  • ideally, post rooms should have independent air conditioning and alarm systems, as well as scanners and x-ray machines. However, while mail scanners may detect devices for spreading chemical, biological and radiological (CBR) materials (e.g. explosive devices), they will not detect the CBR materials themselves. At present, no CBR detectors are consistently capable of identifying all hazards reliably. Post rooms should also have their own washing and shower facilities, including soap and detergent
  • staff need to be aware of the usual pattern of deliveries and to be briefed of unusual deliveries. Train them to open post with letter openers (and with minimum movement), to keep hands away from noses and mouths and always to wash their hands afterwards. Staff should not blow into envelopes or shake them. Packages suspected of containing CBR material should ideally be placed in a double-sealed bag
  • consider whether staff handling post need protective equipment such as latex gloves and face masks (seek advice from a qualified health and safety expert). Keep overalls and footwear available in case staff need to remove contaminated clothing
  • make certain that post opening areas can be promptly evacuated. Rehearse evacuation procedures and routes, which should include washing facilities in which contaminated staff could be isolated and treated
  • prepare signs for display to staff in the event of a suspected or actual attack.

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