Hazards and control measures
Lone working hazards and control measures
The hazards of lone working, who works alone and why it raises the stakes, the high risk work HSE says needs a second person, and the control measures: limits on solo work, agreed check-ins, alarm devices and a tested emergency procedure.
What are the main hazards of lone working?
A lone worker faces the same hazards as anyone else, but if something goes wrong there may be nobody to help, raise the alarm or give first aid. It is often safe and legal to work alone, but the employer must assess the risks first, and some high risk work, such as in a confined space or near exposed live conductors, may need at least one other person present. The usual controls are limits on what is done alone, agreed check-in times, a way to call for help and an emergency procedure that has been tested.
Last updated . Facts checked by the SiteSurvey team on 24 October 2026 against HSE: Protecting lone workers (INDG73), HSE: Manage the risks of working alone and The Confined Spaces Regulations 1997, regulation 5.
Who works alone
HSE describes a lone worker as someone who works by themselves without close or direct supervision. That covers far more people than the night security guard. It includes cleaners, security staff and maintenance and repair staff who work apart from others on the same premises or outside normal hours, engineers and installers who travel between sites, people working at a fixed base such as a shop or warehouse, and the electrician who stays on after the rest of the crew has gone to finish testing and paperwork.
Working alone is not unlawful in itself. HSE's guidance says it will often be safe to work alone, but the law requires the employer to think about and deal with the risks before anyone is allowed to do so. There is no need for a separate lone working assessment: the risks to lone workers belong in the general one.
Who is harmed, and how
Lone workers face the same hazards as everyone else, but HSE notes there is a greater risk of those hazards causing harm because nobody may be there to help if things go wrong. A slip, a fall from a stepladder, an electric shock or a sudden illness that would be dealt with in minutes on a busy site can become serious when nobody knows it has happened. Help is delayed, first aid is delayed, and the person may not be able to call for it.
Violence and aggression are the other main risk. Lone working does not automatically mean a higher risk of violence, but it makes workers more vulnerable. HSE points to late evening and early morning work, security roles with authority over the public, contact with people affected by alcohol or drugs, and carrying cash or valuable equipment. The worker's own health matters too: a medical condition, pregnancy, inexperience or stress can make working alone unsafe, and poor contact can leave people feeling isolated.
What the law expects
The Health and Safety at Work etc Act 1974 and the Management of Health and Safety at Work Regulations 1999 require the risks to be assessed and controlled. Start by removing the lone working where the risk is too high. HSE lists high risk work where at least one other person may need to be present: in a confined space, where a supervisor and someone dedicated to rescue may be needed, near exposed live electrical conductors, and in diving, fumigation and vehicles carrying explosives. The Confined Spaces Regulations 1997 do not allow anyone to enter a confined space until suitable rescue arrangements are in place.
Where work alone goes ahead, set limits on what can be done alone, for example no live testing, no lifting objects too large for one person and no work near an unprotected edge. Then put the supervision and contact around it: pre-agreed check-in times with a named person, a phone or alarm device that works where the person is, a reliable way to confirm they have returned, first aid equipment where the assessment calls for it, and emergency procedures that are practised and tested. In SiteSurvey, the RAMS template has a tick list of these controls against the lone working hazard and scores the risk before and after further action, and the Suggested controls list follows the same order.
Suggested controls
Lone working: control measures, most effective first
These are the 5 controls the SiteSurvey RAMS and risk assessment forms offer for this hazard as a tick list, grouped by their level in the hierarchy of controls. They are a starting point from HSE guidance, not an assessment of your job: tick what applies and say how it works on your site. If only personal protective equipment is ticked, the form says so. How suggested controls work and the hierarchy of controls explained.
Take the hazard away altogether, usually by doing the job a different way or from a different place.
- High risk tasks done only when a second person is present
Keep people away from the hazard with a physical measure: a guardrail, a barrier, extraction, isolation.
- Phone or lone worker device carried and tested
Change the way the work is done: a permit, a check, training, supervision, timing.
- Check-in times agreed and a named person expecting the call
- Supervisor knows where the person is and when they are due back
- First aid kit and the emergency procedure with the lone worker
Offered to: Electrical and M&E, AV, IT and data cabling installation, Facilities, cleaning and maintenance, Grounds, landscaping and tree work.
Try it
Build the controls for lone working
Tick the controls you would put in place, see which levels of the hierarchy they reach, and score the risk before and after. Or fill in the example from a completed RAMS to see how one crew did it.
Interactive
Try it: lone working
Works the same way as the RAMS form. Nothing you tick is saved or sent anywhere.
Your controls, by level
- Eliminatenot ticked
- Substituteno control at this level for this hazard
- Engineeringnot ticked
- Adminnot ticked
- PPEno control at this level for this hazard
Nothing ticked yet.
3. Score the risk with these controls
What the law says
- Health and Safety at Work etc Act 1974, section 2
- The employer's duty to ensure, so far as reasonably practicable, the health and safety of employees, including the information, instruction, training and supervision lone workers need.
- Management of Health and Safety at Work Regulations 1999, regulation 3
- The suitable and sufficient risk assessment, which must include the risks to anyone working alone, recorded where there are five or more employees.
- Confined Spaces Regulations 1997, regulation 5
- No one may enter or work in a confined space until suitable and sufficient rescue arrangements are in place, which in practice rules out working in one alone.
Worked example
Lone working in a completed RAMS
The hazard entry exactly as it was recorded in one of our completed example RAMS: the controls ticked from the list, how they apply on that job, and the score before and after the further action.
Electrical and M&E
Calverley House, Leeds: plant room distribution board and sub-mains replacement
- Hazard
- Lone working: Plant room and the riser, Sunday 18:00 to 21:00
- What could happen, and to whom
- A. Whitfield stays on alone after K. Dhillon and E. Nowak leave at 18:00 on the Sunday to finish the continuity and insulation resistance tests on the new sub-mains and write up the schedule. If he is taken ill, falls or is injured, nobody in the building would know; the only other person on site is the security guard on the front desk two floors up.
- Controls ticked
- High risk tasks done only when a second person is present
- Check-in times agreed and a named person expecting the call
- Phone or lone worker device carried and tested
- Supervisor knows where the person is and when they are due back
- First aid kit and the emergency procedure with the lone worker
- How they apply on this job
- The supply stays locked off until the Monday, so the lone work is dead testing (continuity and insulation resistance on circuits proved dead that morning), labelling and paperwork. No live testing, no work on the landlord's board, no stepladder work and no lifting of anything over 25 kg is done alone; the live tests wait for K. Dhillon on the Monday. A. Whitfield phones P. Garside at 18:00, 19:30 and 21:00 and texts when he is off site; if a call is 15 minutes late P. Garside rings him, then the security guard on the front desk number, then goes to site. His phone is charged and has signal in the plant room (checked on the pre-start visit). The security guard knows he is in the plant room and looks in at 20:00. The first aid kit is on the bench next to him and the emergency procedure card is in his pocket.
- Risk with these controls (likelihood x severity)
- 2 x 4 = 8 (Medium)
- Further action
- Check-in times written on the permit and in P. Garside's diary. Mobile signal in the plant room re-checked at the start of the Sunday; if there is none, the lone session is cancelled and the dead tests move to the Monday morning. Owner: P. Garside.
- Residual risk
- 1 x 4 = 4 (Low)
A fictional job, filled in as a worked example. The form and the report are real.
It also appears in clearing and deep cleaning a void flat. All eleven completed RAMS.
Lone working: common questions
Is it legal to work alone?
Yes, in most cases. HSE says it will often be safe to work alone, but the employer must assess and deal with the risks before anyone does. Some high risk work is different: a confined space needs rescue arrangements in place before entry, and HSE says work near exposed live conductors may need a second person. The answer comes from the risk assessment, not from a blanket rule.
How often should a lone worker check in?
There is no fixed interval in law. HSE expects pre-agreed intervals of regular contact, set by the risk: the higher the risk, the closer the supervision. Agree the times before the work starts, name the person expecting the call and write down what they do if a call is missed, such as ring back, ring the site, then go there. The worked example below uses calls at fixed times and a 15 minute escalation.
Do we need a lone worker device?
Not always. HSE mentions phones, radios and devices that raise the alarm manually or automatically, and the right one depends on the risk and the location. A phone is no use in a plant room or basement with no signal, so check coverage on site first. Whatever is used should be tested regularly along with the emergency procedure.
Can someone with a medical condition work alone?
Sometimes, but it needs thought. HSE advises getting medical advice if you are unsure, and considering both routine work and foreseeable emergencies that put extra demands on the person. Young or inexperienced workers, trainees and people who are pregnant may also be more vulnerable. New workers may need to be accompanied at first.
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