Submitting mandatory occurrence notices and reports
A guide for principal designers, principal contractors and accountable persons to report incidents or risks of structural failure, or the spread of fire to the Building Safety Regulator.
Applies to England
Who must submit mandatory occurrence notices and reports
Principal designers and principal contractors
Principal designers and principal contractors must submit mandatory occurrence notices and reports, during:
- construction of a new higher-risk building
- work on an existing higher-risk building, including work that causes it to stop being a higher-risk building
- work on an existing building that will make it a higher-risk building
A higher-risk building is a building that has at least:
- 7 storeys or is at least 18 metres high
- 2 residential units or is a hospital or a care home
You can read guidance about the criteria that makes a building a higher-risk building.
Accountable persons
A higher-risk building with at least 2 residential units must be registered with the Building Safety Regulator (BSR) before people live there.
Accountable persons must submit mandatory occurrence notices and reports for the parts of the high-rise residential building they are responsible for.
What to report to BSR
You must submit a mandatory occurrence notice and report when a safety occurrence has caused, or is likely to cause:
- the death of a significant number of people
- serious injury of a significant number of people
A safety occurrence is an incident involving, or a risk that could cause:
- structural failure of the building
- the spread of fire or smoke in the building
A safety occurrence is something which if not remedied, could cause serious harm to people when the building is in use.
You must submit a report even if the safety occurrence is remedied immediately. The only exception is when a principal contractor remedies issues to ongoing building work, which are unlikely to risk significant numbers of death or serious injury.
Failing to report
You’re committing an offence if you do not make a report and could face enforcement action, including prosecution.
If you know that a mandatory occurrence report has already been submitted to BSR, you do not need to submit a report for the same safety occurrence. You should obtain a copy of the report submitted to BSR to support your decision not to make the report yourself.
Reporting incidents to the fire service
If you report an incident to the fire service, you must also submit a mandatory occurrence notice and report if it meets the criteria of what to report to BSR.
Duties of principal designers and principal contractors
As a principal designer or principal contractor, you must submit mandatory occurrence notices and reports during construction or building work of higher-risk buildings.
The notices and reports relate to the building that is under construction or undergoing building work. They do not relate to safety incidents relating to the construction site in general or any temporary structures.
You must establish and operate a mandatory occurrence reporting system for others to report safety occurrences to you for review.
Find out more about the roles of principal designers and principal contractors in the guide design and building work: meeting building requirements.
Safety occurrence examples
Some examples that could meet the criteria of what to report to BSR, include:
- defective building work, including defective competent person scheme work which is part of the wider building work
- fire safety issues likely to result in the spread of fire
- the use of non-compliant products or incompatible compliant products in the construction of the building
- inappropriate or incorrect installation of construction products
- product failure against specification and claimed performance
- faults in the design plans, caused by either design software or human error
Change control applications
If you submit a mandatory occurrence report, you may also need to make a change control application.
For example, during construction you discover the load points in the design plans have been miscalculated. If this is not remedied, it could cause structural failure and risks death or serious injury to a significant number of people when the building is in use. This meets the criteria of what to report to BSR and you must submit a mandatory occurrence notice and report.
To correct the plans, the principal contractor must also submit a change control application and request a major change to the building control application.
Transitional arrangements
If the higher-risk building in construction is subject to the transitional arrangements, you may not need to submit mandatory occurrence reports for it.
Read the transitional arrangements for the higher-risk regime factsheet to understand reforms to building work processes and their regulations.
Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (RIDDOR)
During building work, if someone has died or has been injured because of a work-related incident you may need to make a RIDDOR report. For example, if someone has fallen from scaffolding and has died.
If an incident is reported under RIDDOR, you must also submit a separate mandatory occurrence notice and report if the incident meets the criteria of what to report to BSR.
For example, during building work, part of a building collapses and injures people. The principal contractor reports the incident under RIDDOR. The principal contractor also submits a mandatory occurrence notice and report, as the incident involves structural failure, which if not remedied risks death or serious injury to a significant number of people when the building is in use.
You can find out about what must be reported under RIDDOR on the HSE website.
Duties of accountable persons
As an accountable person, you must submit mandatory occurrence notices and reports to BSR for the parts of the high-rise residential building you are responsible for.
Safety occurrence examples
Some examples that could meet the criteria of what to report to BSR when the building is occupied by residents, include:
- the spread of fire
- total or partial collapse of the building
- defective building work
- unexpected failure or the degradation of construction materials
- the discovery of structural defects
- failure of a critical fire safety measure, such as an automatic opening vent, smoke extraction or fire doors
The principal accountable person must establish and operate a mandatory occurrence reporting system for residents and others to report safety occurrences to the accountable persons.
Safety case
You should include all safety occurrences in the building’s safety case.
Safety occurrences before January 2024
If a safety occurrence was identified before January 2024, you must make a mandatory occurrence notice and report if one of the following applies:
- after taking into account any safety measures that are in place, it still meets the criteria of what to report to BSR
- the risk has worsened and now meets the criteria
When to report to BSR
When a safety occurrence happens or is identified that meets the criteria of what to report to BSR you must submit a:
- notice as soon as you can
- report within 10 days of the safety occurrence being identified
How to report to BSR
You can submit a mandatory occurrence notice and report online.
Submit a notice
You will need to provide:
- your contact details
- the address of the building where the incident or risk has been identified
- the date the incident or risk was identified
- a brief description of the incident or risk
- any immediate actions you’ve taken to keep people safe
When you submit a notice, we’ll give you a reference number which you can use to submit a mandatory occurrence report.
Submit a report
You must submit a report after submitting your notice. You can give us the full report immediately after submitting the notice if you have the information available.
You will need to provide:
- your mandatory occurrence notice reference number
- the building registration application reference or address if the building is occupied
- the building control application reference number if the building is in design or construction and construction work has started
- your contact details, the name of your organisation and its involvement in the building
- the incident or risk you are reporting and when and how you became aware of it
- what happened, or has the potential of happening
- who is involved and the effect on them
- what you have done and plan to do to keep people safe
- any supporting information, such as documents, videos or photos
Missing information
If you intend to gather more information after submitting the report, tell us when you expect to have it. We’ll also contact you if we need any extra information.
Other ways to report
You can also call us on 0300 790 6787
Monday to Friday, 8:30am to 5pm (except Wednesdays when we are open from 10am to 5pm, and public holidays when we are closed).
If you would prefer to speak to us on the phone in a language other than English, a translation service is available.
Standard call charges will apply.
After submitting a report to BSR
We’ll review the report and determine the severity of the safety occurrence. We’ll also review any safety measures that are in place, and if they are sufficient to manage the risk.
We will contact you if we:
- need further information
- decide the incident or risk did not need to be reported
- need to start an investigation
During an investigation, we’ll review the findings and decide if any action is needed.
There are no charges for making a mandatory occurrence notice and report, but investigations do incur cost recovery charges. You can find out more about BSR’s charging scheme on the HSE website.
The information on this page is not intended to be guidance under section 108 of the Building Safety Act 2022.
Last updated 4 March 2024 + show all updates
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Information and link to related guidance added about principal designers and principle contractors
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First published.