Fire involving explosives

Question 1

Initial action

Answer 1

Step 1
Remember that there may be a secondary device anywhere at the scene, including in a nearby building or vehicle. Do not handle or interfere with anything unfamiliar.

Step 2
Do not use cell phones, portable radios or other transmitting devices.

Step 3
Evacuate the scene to a distance of at least 100m. Ensure that people leaving the scene bring their personal possessions with them. This will limit the number of items to be cleared. Consider using an explosives detector dog to locate the device.

Step 4
If the IED is located, immediately obtain the assistance of an IED operator from the Department of Labour. If not Department of Labour operators are available, consider utilising a Defence Force expert. Bear in mind that the expertise of Armed Services operators relates primarily to military ordinance.

Step 5
Give regular SITREPS to the Police Emergency Communications Centre.

Question 2

Examining the scene of a fire involving explosives

Answer 2

Step 1
Once the scene has been declared safe, conduct a scene examination. Use video and photographs, as these are useful as a briefing tool and court record.

Step 2
Remember to continually reconstruct.

Step 3
Request the attendance of a suitably experienced ESR analyst. Ask them to bring suitable material for swabbing the scene and for swabbing hands, and examining the clothes, of any suspects.

Question 3

Identifying the explosive

Answer 3

Step 1
Give priority to identifying the explosive used, as this evidence will be cruicial to a prosecution. The expert may be able to advise the likely type of explosive from an examination of the nature of the damage done. Remember that initial specialist opinion on the nature of the explosive may be overturned by scientific analysis. As a general rule, the more powerful the explosive, the less residue it leaves and the more directed the explosion.

Step 2
A low powered explosive will explode in a general manner, causing damage and spearding debris over roughly the same distance in all directions. Such exposives need to be confined - for example, in a pipe - to have any real effect. A low powered explosive can become a high powered explosive through such confinement.

Step 3
Expolsives that explode at a rate of 1200 - 5000 metres per second (mps) are characterised by the fact that damage occurs in a ‘least line of resistance’ pattern. This means that windows, doors and light walls blow out.

Step 4
Explosives that explode at a rate greater than 5000 mps do so in a directional manner. Sometimes they explode straight up and down in a definable blast pattern, causing great directional damage, and items that miss the directional blast are not as seriously damaged as might be expected. A person who is experienced in explosives can make an IED that will perform in this way.

Step 5
Because modern explosive residues are often slight and dissipate rapidly, the O/C scene may need to authorise the expert to enter the centre of the scene before it has been fully examined. In this case:
- create a path to the centre of the explosion, by laying a clean unused roll of plastic or by using approved stepping plates (this may involve some exhibits being trampled underfoot)
- have the ESR analyst start swabbing the area immediately (wor kutwards from the seat of the explosion)
- vertical sheets of iron adjacent to the blast, such as street signs and fencing, are often good sources of residue.
Ensure that the items used (including tools and so on) are all carefully cleaned before use. Discuss the avoidance of cross-contamination with the ESR analyst.

Step 6
It may also be necessary to remove body parts promptly, before they decompose and animal and insect activity contaminates the scene. The same clean path method should be used.

Step 7
Record your impressions of any odours you detect.