Procedure for Registration of Explosives Manufacturing Processes under RIDDOR Exemption No 4 of 2007


Issue date:
September 2011
Review date:
September 2014
To provide staff with guidance on procedures for dealing with applications for registration of specific explosives manufacturing operations or processes to be exempt from the requirement for reporting of unintentional ignitions as dangerous occurrences under RIDDOR.
OG status:
Fully Open,
Author unit / section:
Target audience:
Explosives Inspectors (for action), HSL Explosives Section, Quarries Inspectors, Mines Inspectors, FOD/HID Inspectors (for information)
Version No:


To provide staff with guidance on procedures for dealing with applications for registration of specific explosives manufacturing operations or processes to be exempt from the requirement for reporting of unintentional ignitions as dangerous occurrences under RIDDOR.


1. Prior to the introduction of the Manufacture and Storage of Explosives Regulations 2005 (MSER), unintentional fires or explosions that occurred at sites licensed under the Explosives Act 1875 were reportable under Section 63 of that Act and were exempt from reporting under RIDDOR. MSER revoked most of the Explosives Act (including Section 63) and amended RIDDOR to make ignitions at sites licensed under MSER reportable as dangerous occurrences defined in schedule 2 Part 1/6.

2. This change had an unintended consequence, which was overlooked at the time, whereby certain unintentional minor ignitions and explosions where a failsafe device or safe system of work functioned so as to prevent injury, are reportable if they occur at a site licensed under MSER, but are not reportable if they occur elsewhere (and never have been).

3. Under the amended RIDDOR, the explosives industry has a problem with what used to be termed "covenanted ignitions" when sites were licensed under the Explosives Act. Covenanted ignitions were those ignitions that happened from time to time, despite the measures taken to prevent them. They usually involved explosives that are particularly sensitive and as a consequence much of the processing is done remotely, on small quantities. Section 63 of the Explosives Act required notification of ignitions to HSE "forthwith". By agreement with HSE, covenanted ignitions were not required to be reported forthwith, and periodic returns were made. HSE did not investigate these ignitions, nor were they included in statistical returns. Ignitions of this sort do not result in damage to the building or plant, but may result in damage to the tooling involved. After a clean up and replacement of tooling, work would normally be able to re-start quite quickly. This administrative arrangement was not promulgated under MSER, Schedule 2 paragraph 6 of which made these types of ignition reportable under RIDDOR.

4. Exemption certificate No 4 of 2007 (TRIM 2007/97752) made under RIDDOR exempts these minor unintended ignitions from the requirement for reporting as dangerous occurrences, provided the conditions are met

5. Ignitions will only be considered to be eligible for registering under the exemption if they meet a number of conditions:

  • The risk of ignition must be anticipated, and must be addressed by specific control and mitigation measures.
  • There will be a residual risk of ignition, even after all reasonably practicable measures to prevent ignition have been taken. The eligible operations will usually involve sensitive explosives.
  • The operation must be carried out remotely or with sufficient protective measures in place to prevent injury to people and to prevent any communication of fire or explosion beyond the explosives immediately involved.
  • When ignitions occur, there should be no damage to the building or plant, but there may be tooling damage.
  • Action needed to recover following an ignition does not put people at additional risk due for example, to exposed explosives.

Application Procedure

6. Each Company (site) will need to apply to register processes for the exemption. The inspector should discuss the details with the company to come to an initial view on whether the ignition is likely to meet the criteria.

7. If this is the case, the information to be supplied with the application will need to provide sufficient information to allow the inspector to make a proper assessment. As a minimum it should include:

  1. Company and site name
  2. Reason for the application – What causes the ignitions and why they cannot be eliminated.
  3. Details of the process/operation to be exempted
    1. Building
    2. Compartment
    3. Operations
    4. Machine
    5. Explosives involved
    6. Maximum quantity of explosives involved (weight and/or units).
  4. Justification – measures in place that minimise the risk.
  5. The expected frequency and effects of ignitions.

8. One way of gathering this information is for the company to fill out the relevant parts of the registration report at Annex 1.


9. The Inspector assesses whether the proposal meets the criteria for exemption

  1. The process is a manufacturing process; incidents during storage are not eligible for exemption.
  2. The ignition is anticipated – there is a history of minor ignitions, it's not just something that "might happen".
  3. All reasonably practicable measures have been taken to prevent ignitions and to limit the consequences.
  4. The protective measures in place are robust and prevent injury to people and damage to plant and buildings.
  5. The action needed to recover following an ignition should not put people at additional risk eg through the presence of significant quantities or exposed explosives.

10. The inspector should check that worker representatives on the site have been consulted by the company and are in agreement with the proposal to register for exemption.

11. The request for registration and the assessment of such requests is not intended to be a major task, nor bureaucratic. The extent of evidence required should be fit for purpose. There is an expectation that incidents, which under the 1875 Act were considered as "covenanted ignitions", will be agreed under this procedure.

12. On completion of the assessment, the inspector completes a "Registration Report" that captures and defines the exempt ignition. The purpose of this is to record details of the ignition, plant, protective measures and explosives concerned. An example format is at Annex 1.

13. The completed form should be passed to the B2 team leader for endorsement. Where the report is prepared by a B2, it need not be endorsed by another B2.

14. Once agreed, the inspector records this in a letter to the company, confirming each ignition to which the exemption applies. An example letter format is included at Annex 2. Copies of the relevant registration report(s) should be attached to the letter. A copy of the registration report should be put in TRIM Folder Example File Name: RIDDOR Exemption No 4 of 2007 - RIDDOR 5 BAE Systems Radway Green Manurhin PC 380. A note should also be put on the COIN record for the site with a reference to the TRIM record for the report.

15. A list of the exempted ignitions is to be maintained on TRIM in Explosives – Exemption Certificates (Record No 2010/229724), with a hard copy on file XI/0005/282. The next exemption number should be allocated at a suitable point in the process and the register marked accordingly.

16. In the unlikely event that a proposal for registration has been formalised in a report and is not supported by the inspector, the company are to be advised of the decision by letter with an explanation of the reasons. The register should also be marked up that the registration was not supported

Annex 1

Registration Report for Explosives Manufacturing Processes Exempted under RIDDOR Exemption No 4 of 2007

Annex 2

Draft letter recording that ignitions no longer need be reported as DO's in accordance with RIDDOR CE No 4 of 2007.



In accordance with condition 2(c) of Certificate of Exemption No 4 of 2007 made under Regulation 13 of RIDDOR, the Health and Safety executive hereby confirms registration of the following process(es) at [site]

In accordance with the conditions of that Certificate of Exemption, unintentional ignitions on these processes, detailed in the attached registration report, ref RIDDOR/XX dated XXXXXX, are exempt from the requirement to report them as dangerous occurrences.

In order to allow both you and HSE to monitor trends in these ignitions, you should keep a log of the date, time and explosives involved for each such ignition. This record should be kept available for examination by inspectors on request.

This exemption does not relieve you of your duty to investigate the causes of any ignitions on these processes. You should notify HSE of any proposed changes to the explosives, process or plant that could affect the exemption or materially affect the frequency or consequences of ignition.

Yours sincerely

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Updated 2020-12-09