Screening Mail and Courier Deliveries

PAS 97: 2021 Mail screening and security - Specification

Mail Screening Matters - NPSA's mail screening and security campaign

To increase the level of understanding and uptake of the information contained within PAS 97, NPSA has produced a range of guidance products on postal security. The Mail Screening Matters campaign materials are aimed at a range of audiences, from general awareness products for non-mail handling staff, recognition and response guidance for front-line mailroom staff, to convenient materials for security managers who are assessing and implementing screening and security measures.

Postal threats

Terrorists and others wishing to cause harm or disruption have long used postal and courier services to deliver hazardous items to target recipients. 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 can include letters, packets and parcels and may contain:

• explosive or incendiary devices
• sharps or blades
• offensive materials
• chemical, biological, radiological or nuclear (CBRN) materials (either bulk or small / discrete quantities) or devices.

NOTE: "White powders" are often referred to in the context of mail threats. These can include hazardous chemical (including explosive or narcotic), biological or radiological materials, as well as benign materials. It is important also to note that such materials may not be "white" and may not be "powders"; materials may be crystalline (e.g. sugar), oily or waxy residues, or liquids.

Anyone receiving a suspicious delivery is unlikely to know exactly 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 any device is unlikely to function through being moved, but any attempt at opening it may set it off. In contrast, even gentle handling or movement of an item containing CBRN material could lead to the release of contamination. 

Delivered items come in a variety of shapes and sizes; a well-made one will look innocuous but there are many possible indicators that a delivered item may be of concern.

Bulky deliveries (e.g. office equipment, stationery and catering supplies) are also a potential vulnerability. This risk can be reduced through measures such as: matching deliveries against orders, only accepting those which are expected; using trusted suppliers wherever possible; maintaining vigilance; inspecting deliveries.

General protective measures

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. 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.

Ensure that all staff who handle and open mail and other deliveries are and remain aware of the possible indicators that a delivered item may be of concern, and the appropriate action upon discovery of any suspicious delivered item. While this advice applies particularly to staff in post rooms, it is also relevant to all staff who may be the recipients of such items, as well as staff at entrances who may receive hand and courier delivered items. Encouraging regular correspondents to put their return address on each item, and in particular to provide advance warning of unusual items can help reduce false alarms.

Post rooms

Rather than merely being used to sort mail and deliveries, post rooms can be used to provide significant protective security benefits. All incoming post (including Royal Mail, and courier and hand delivered items) should be channelled through the post room and its screening systems. It is therefore important to understand all of the routes by which post is received, and ensure that urgent items do not circumvent the system.

A basic but extremely worthwhile level of protection can be achieved by post room staff looking out for suspicious items, or better still inspecting each item briefly. Post room staff should be well aware of the possible indicators that a delivered item may be of concern, and the appropriate action upon discovery of any suspicious delivered item. As already noted, the exact nature of a suspicious delivery may well not be immediately obvious hence this advice is designed to applicable in a wide range of situations.

Post rooms should ideally be located off-site or in a separate building, thereby minimising the disruption to business if there is an incident. If the post room cannot be located in a separate building, it should at least be in an area that can easily be isolated and in which deliveries of mail can be received directly, without taking them through other parts of the building. The air handling system for such a post room should ideally be separate from that of the rest of the building, with pressure gradients such that air flows into the post room from other parts of the building rather than vice-versa.

Post room staff should have ready access to hand-washing facilities and should wash their hands before breaks and after work.

Using X-ray systems to screen mail

X-ray machines can be used to screen mail for the presence of hazardous items such as blades and explosive, incendiary or CBRN devices. They will not, however, reliably enable detection of small amounts of loose CBRN materials or "white powders", especially if multiple items are X-rayed simultaneously (any container should, however, show up). X-ray machines are available in a wide range of models offering different detection capabilities and throughputs. Any organisation planning to procure such screening solutions should satisfy itself, where necessary seeking independent expert advice, that the capability provided meets its operational needs.

A UK Mail Screening Test Piece (MSTP) has been designed for mail screening applications to monitor X-ray system image quality standards. The MSTP is recommended for checking regularly that the system is performing to the expected standard. UK Mail Screening Test Piece (MSTP) - A Guide gives a description of each individual test outlining the purpose of the test, its applicability to conveyorised and /or cabinet X-ray systems, and the particular relevance of the test to mail screening. The Engineering Drawings for the UK Mail Screening Test Piece (MSTP) are also available.

CBRN threats

Organisations which assess themselves as being at particular risk of CBRN postal threats should seek advice as to whether they should consider specialist facilities such as air handling systems, protective equipment and cabinets or other physical or procedural protective measures. Further information is available from the CBRN Threat Specific Mitigation page.