Dynamic risk assessment: meaning, the law and examples

A dynamic risk assessment is the check a trained worker makes on the job, as conditions change, to decide whether work can carry on, needs another control or must stop. No regulation uses the term. It supplements your risk assessment and never replaces it. The risk assessment is the legal duty, under regulation 3 of the Management of Health and Safety at Work Regulations 1999, which applies in Great Britain.

Regulation 3(6) of the same Regulations, MHSWR 1999 for short, also requires you to record the significant findings of that assessment if you employ five or more employees. Northern Ireland has its own Regulations, from 2000, with the same duty on employers to assess risk. The dynamic assessment covers the detail a written assessment cannot fix in advance, such as the ground at a customer's drop point or the weather on the day.

What is a dynamic risk assessment?

HSE's lone working leaflet, INDG73, describes it as the situation "where workers themselves make operational decisions based on risks which cannot necessarily be foreseen". The same passage says it is no substitute for a full risk assessment.

The term also appears in fire and rescue incident command. The government's Fire and Rescue Manual on incident command, third edition 2008, uses it for the continuing assessment of risk at incidents, in a rapidly changing environment. In that manual the dynamic assessment rests on generic risk assessments written beforehand, and should be supported by an analytical risk assessment at the earliest opportunity.

Away from emergencies, the written assessment foresees the kind of situation, such as deliveries to customer sites or call-outs to a breakdown, and the person on the job deals with the detail of each one.

	Risk assessment	Dynamic risk assessment
Legal basis	Regulation 3 of MHSWR 1999	No regulation names it. It is how trained staff apply the risk assessment on the day
Made by	The employer, or a competent person helping them	The worker doing the job, within limits the employer sets
When	Before the work, then reviewed under regulation 3(3) of MHSWR 1999 if there is reason to suspect it is no longer valid or there has been a significant change	At the start of the job and whenever conditions change during it
Covers	The risks the work foreseeably brings, to staff and to anyone else affected	What has changed on that site, that day
Recorded	Significant findings, if you employ five or more employees	Optional. A short note of what changed helps the review
Outcome	Controls, training, procedures and who does what	Carry on, add a control the assessment allows, or stop and call for help

Is a dynamic risk assessment a legal requirement?

No Act or regulation uses the phrase. What the law requires is the risk assessment, and several duties around it decide whether a decision made on the job can safely be left to the person there.

Provision	What it requires
Regulation 3(1) of MHSWR 1999	A suitable and sufficient assessment of the risks to your employees, and to people not in your employment arising out of or in connection with your undertaking, to identify the measures you need to take
Regulation 3(3) of MHSWR 1999	A review if there is reason to suspect the assessment is no longer valid, or there has been a significant change, and any changes the review shows are needed
Regulation 3(6) of MHSWR 1999	With five or more employees, a record of the significant findings and of any group of employees identified as especially at risk
Regulation 8 of MHSWR 1999	Procedures for serious and imminent danger, which enable people to stop work and go straight to a place of safety when exposed to serious, imminent and unavoidable danger, taking appropriate steps without guidance or instruction if necessary
Regulation 13(1) of MHSWR 1999	Taking account of employees' capabilities as regards health and safety when you give them tasks
Section 2(2)(c) of the Health and Safety at Work etc. Act 1974	The information, instruction, training and supervision necessary for your employees' health and safety, so far as is reasonably practicable
Section 7 of the Health and Safety at Work etc. Act 1974, and regulation 14 of MHSWR 1999	Employees take reasonable care, and tell you about any work situation or matter that someone with their training and instruction would reasonably consider a serious and immediate danger, or a shortcoming in your protection arrangements

So the duty stays with the employer throughout, and a dynamic assessment is a decision the employer has prepared a worker to make. HSE's INDG73 says what that preparation involves. Where a risk assessment identifies circumstances in which a lone worker may have to make a dynamic risk assessment, HSE says they must be trained to make it, consider the range of possible control measures and what action to take, and get support for their decisions.

Our guide to the Management of Health and Safety at Work Regulations covers the 1999 Regulations as a whole.

Does a dynamic risk assessment have to be recorded?

The recording duty in regulation 3(6) of MHSWR 1999 attaches to the risk assessment, and there is no separate duty to record each dynamic assessment. The two meet at review. If a dynamic assessment shows the risk assessment has missed something, that can be reason to suspect it is no longer valid under regulation 3(3) of MHSWR 1999, and any change goes into the record.

HSE's guidance on managing risk puts the priority on controlling the risks in practice, ahead of the paperwork. It also says to consider a review when workers have spotted problems, or after accidents or near misses. A short note made on the job gets that information back to whoever owns the assessment.

How to carry out a dynamic risk assessment

No regulation sets a method. In the sequence we suggest, the worker:

1. Stops at the start of the job, and again whenever something changes.
2. Compares what is in front of them with what the risk assessment, and any method statement, assumed.
3. Works out what has changed, who could be hurt by it and how badly.
4. Chooses from the options the assessment gives: carry on, add a control it allows, or stop and call the named contact.
5. Reports what they found once the job is safe, so the assessment can be reviewed.

Step 4 is where the preparation shows. A worker can only choose a control they know about and are allowed to use, and they need to know the company will back a decision to stop.

What the employer sets up first

Before anyone is asked to make these calls, the risk assessment should set out:

• which situations call for a dynamic assessment
• the controls the worker may use on their own authority, and those that need a supervisor's agreement
• when work stops, and the named person to call
• how findings come back to whoever owns the assessment

HSE's lone working guidance asks employers to set limits on what can be done while working alone, and to make sure workers can recognise when they should get advice. It suggests supervising a new worker at first when they are dealing with new situations. Under section 2(2)(c) of the Health and Safety at Work etc. Act 1974, you provide the training and supervision necessary for your employees' health and safety, so far as is reasonably practicable. Treat a dynamic assessment as a skill to train, with practice on the situations your staff will meet.

When a dynamic assessment is the wrong tool

Two kinds of risk belong in the risk assessment itself. The first is a hazard that comes back. If your drivers meet the same tight access at the same customer every week, that is a known hazard, and the control should be agreed in advance. HSE's guidance on managing risk asks you to take account of non-routine operations too, such as maintenance and cleaning, when you identify hazards.

The second is a planned change. New equipment, a new process or a new location can be a significant change under regulation 3(3) of MHSWR 1999, and a reason to review the risk assessment before the work starts. Our guide to planning new and non-routine work covers the triggers for that review.

The options open to the worker are the ones the risk assessment gives them, and stopping should always be one of them.

Dynamic risk assessment examples

These come from the kinds of site we work on. In each, the written assessment set out the options before the day.

Situation	What the risk assessment set up beforehand	The decision on the day
A builders merchant driver arrives to deliver with a lorry loader crane. The planned drop point is soft ground beside an excavation, and people are walking through the unloading area	Crane deliveries assessed as a task. Drivers trained to check the ground, overhead lines and the path of the load, and allowed to refuse a drop	Set up on firm ground away from the excavation, cone off the lift area and lift only when it is clear, or refuse the drop and phone the branch
A warehouse picker finds fresh impact damage on a racking upright partway through a shift	A reporting route for racking damage, and who can take a bay out of use	Stop using the bay, keep people clear and report it, so the damage is assessed before the bay is used again
A maintenance worker is on a ladder at a garden centre when the wind picks up and rain turns to sleet	Weather limits for work at height, and who decides when they have been reached	Come down, make the area safe and report it so the job is rebooked

The crane delivery is also a lifting operation. Regulation 8 of the Lifting Operations and Lifting Equipment Regulations 1998 (LOLER) requires every lifting operation to be properly planned by a competent person, and HSE's guidance says a simple, routine lift may need little more than on-the-job planning by trained, competent people. That on-the-job planning is where the driver's dynamic assessment happens. Our LOLER guide covers the planning duty.

The ladder job turns on regulation 4(3) of the Work at Height Regulations 2005, which requires work at height to be "carried out only when the weather conditions do not jeopardise the health or safety of persons involved in the work". The duty is the employer's. The worker on the ladder is the one who sees the weather change, so the risk assessment should give them the authority to come down. Our Work at Height Regulations guide covers those Regulations as a whole.

Frequently asked questions

Is a dynamic risk assessment a legal requirement? No Act or regulation requires one by name. The law requires a suitable and sufficient risk assessment under regulation 3 of MHSWR 1999. Where a lone worker may have to make one, HSE's lone working leaflet, INDG73, expects them to be trained to make it and supported in their decisions.

Does a dynamic risk assessment need to be written down? There is no legal duty to record each dynamic assessment. Regulation 3(6) of MHSWR 1999 requires employers with five or more employees to record the significant findings of their risk assessment. If a dynamic assessment shows that assessment has missed something, review it under regulation 3(3) of MHSWR 1999 and record the change.

What is the difference between a risk assessment and a dynamic risk assessment? The risk assessment is made by the employer, or a competent person helping them, and covers the risks the work foreseeably brings. The dynamic assessment is made by the worker on the job and deals with what has changed since.

Who carries out a dynamic risk assessment? The person doing the work, within limits set by the employer's risk assessment. On a team job, the risk assessment should say who makes the call.

Can a dynamic risk assessment replace a written risk assessment? No. HSE says it is no substitute for a full risk assessment, and the duty in regulation 3 of MHSWR 1999 is to make the risk assessment itself.

Can a worker stop a job after a dynamic risk assessment? Yes. Regulation 8 of MHSWR 1999 requires procedures that enable people to stop work and go straight to a place of safety when exposed to serious, imminent and unavoidable danger. In Great Britain, section 44 of the Employment Rights Act 1996 protects workers from detriment, and section 100 of the Employment Rights Act 1996 makes dismissing an employee unfair, where the reason is that they left, or refused to return to, their place of work in danger they reasonably believed was serious and imminent and could not reasonably have been expected to avert.

What is an example of a dynamic risk assessment? A merchant's driver arrives to deliver with a lorry loader crane and finds the planned drop point on soft ground beside an excavation. The driver sets up on firm ground away from the excavation and cones off the lift area, or refuses the drop and calls the branch, as the company's risk assessment for crane deliveries allows.

Where to start

Pick one job your staff do away from base, or one that changes from day to day. Read its risk assessment and check it names the situations where the worker decides on the day, the controls they may use, when they stop and who they call. Then check the people doing that job have been trained on it.

Many of our consultants are former HSE and local authority regulators. Through the Opus Safety Partnership, a dedicated consultant who knows your sites writes your risk assessments for you, and our risk assessment training is delivered at your premises for anyone responsible for identifying, assessing or controlling risk.