London Police: Letter Bombs Intended to Shock, Not Kill

Post rooms

Delivered items, which include letters, 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.

Delivered items 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 delivered item 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. Delivered items 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 suspicious delivered item:

• 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 or unusual 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 post 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 post are briefed and trained. Include
  reception staff. Encourage regular correspondents to put their return
  address on each item
• ensure that all sources of incoming post (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 post scanners
  may detect devices for spreading chemical, biological and radiological
  (CBR) materials (e.g. explosive devices), they will not detect the CBR
  materials themselves. A range of commercial CBR detection technology is
  available. In the first instance, seek advice from your local police
  force Counter Terrorism Security Adviser. 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
  route, 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.

Source Courtesy of cpni.gov.uk