Summary
In short
- The first question is why the work is done alone. Where the answer is scheduling convenience rather than necessity, changing the schedule is a control the assessment should reach before considering devices.
- Escalation must trigger automatically. Any arrangement depending on a colleague noticing an absence fails during handovers, holidays and busy periods, which is exactly when lone working increases.
- Aggression and violence affect lone workers disproportionately and are reported by them least, because there is no witness and often no immediate outlet.
- California's SB 553, in force since 1 July 2024, requires most employers with any California location to maintain a written workplace violence prevention plan, a violent incident log and annual training, with a separate healthcare standard already in place.
- Cal/OSHA was required to propose a general industry workplace violence standard by December 2025 with adoption due by the end of 2026, while federal OSHA rulemaking has not produced a proposed rule.
- Time to discovery is the survival factor for a medical emergency or an injury while alone, and it is the number the assessment should be driving down.
What it is
What it is
What is lone working?
Working without close or direct supervision, which includes people working alone at a fixed site, mobile workers visiting premises, people working outside normal hours in an occupied building, and anyone whose colleagues are present but out of sight and earshot. The last category is the one most often missed.
Is lone working prohibited?
Generally no, with specific exceptions. Permit-required confined space entry requires an attendant, and some jurisdictions prohibit lone work for particular high-risk activities such as live electrical work or certain lifting operations. Otherwise it is permitted subject to assessment and adequate arrangements, which is where the obligation actually lies.
When to use it
When to use it, and when not to
This assessment covers work performed without close supervision. Where a specific regime prohibits lone work, that takes precedence.
Use it for
- Fixed-site work outside normal hours, including opening, closing and night shift
- Mobile and field work, including home visits, deliveries and service calls
- Partial lone working: colleagues present but out of sight and earshot, or during breaks and handovers
- Work where aggression from members of the public or service users is credible
- Any change to staffing, hours, site layout or task that creates lone working where there was none
Not for
- Confined space entry, where an attendant is mandatory and lone entry is prohibited
- The workplace violence prevention plan, which in California is a specific statutory document with defined content
- Personal safety device specification, which follows the assessment rather than substituting for it
- Fatigue and shift assessment, which addresses a different exposure that frequently coincides
- Business continuity arrangements for out-of-hours incidents, which respond rather than assess
Standards
What it is built against
Lone working is regulated through general duties rather than a dedicated standard, alongside a fast-moving set of workplace violence requirements.
| Clause | Requirement | Where it lands |
|---|---|---|
| ISO 45001 cl.6.1.2 | Hazard identification covering work organisation, including working alone and outside normal hours | Header |
| OSHA General Duty Clause | Duty to address recognised hazards, including violence and delayed rescue where no standard applies | Hazards while alone |
| HSE INDG73 and Management Regs reg.3 | Risk assessment covering lone working with arrangements for supervision and emergencies | Header |
| Cal Labor Code 6401.9 | Workplace violence prevention plan, violent incident log, training and post-incident investigation | Hazards while alone |
| OSHA 1910.146 | Permit-required confined space entry requires an attendant; lone entry is prohibited | Outcome |
| Safe Work Australia model regs | Remote or isolated work requiring a system of work including effective communication | Raising the alarm |
| ISO 45001 cl.8.2 | Emergency preparedness and response, tested and revised, covering out-of-hours conditions | Raising the alarm |
| ISO 45001 cl.5.4 | Consultation with workers, who know which situations actually feel unsafe | Outcome |
What it does not cover
- The workplace violence prevention plan, which in California is a statutory document with prescribed content and retention.
- Confined space entry arrangements, where an attendant is required and lone entry is not permitted.
- Device specification and procurement, which should follow the assessment rather than lead it.
- Fatigue assessment, which addresses a coinciding but distinct exposure.
- The violent incident log, a separate record with its own required fields and five-year retention in California.
Filling it in
Filling it in well
Four things decide whether the assessment produces protection or paperwork.
Necessity, scheduling, cost, or nobody has looked at it. Where the answer is anything other than necessity, the assessment has found a control that removes the exposure rather than managing it. This question is above the device in the hierarchy and takes about a minute to ask.
State the check-in interval, what counts as a missed check-in, how long before escalation, who is contacted, and what they are expected to do. The trigger must be automatic. Arrangements relying on someone spotting an absence fail during precisely the conditions that produce lone working in the first place.
Lone workers face more aggression and report less of it. Where the role involves the public, cash, service users in distress, home visits or enforcement, the assessment should cover it directly, and in California it connects to a statutory plan and incident log rather than to a general incident report.
For a medical emergency, a fall or an injury while alone, the survival factor is how long before anyone knows. That is a measurable number, and reducing it is what the whole arrangement exists to achieve. Test it by missing a check-in deliberately, at a time that matters.
Audit findings
Common audit findings
Lone working findings concentrate on the escalation that was never tested.
| Finding | Clause | What fixes it |
|---|---|---|
| Escalation depends on a colleague noticing a missed check-in. | ISO 45001 cl.8.2 | Automate the trigger; observation-based escalation fails during handovers and busy periods. |
| Arrangement never tested outside working hours. | ISO 45001 cl.8.2 | Test at 2am on a weekend; a Tuesday morning test proves almost nothing. |
| Partial lone working not identified: colleagues present but out of sight and earshot. | ISO 45001 cl.6.1.2 | Assess by whether help would arrive, not by whether anyone else is on site. |
| Device provided without addressing whether the work must be done alone. | ISO 45001 cl.8.1.2 | Ask the scheduling question first; it sits above the device in the hierarchy. |
| Aggression not assessed for roles involving the public or home visits. | General Duty Clause | Assess it directly; lone workers experience more and report less. |
| California location without a written workplace violence prevention plan. | Cal Labor Code 6401.9 | Required since July 2024 for nearly all employers with a California location, regardless of headquarters. |
| On-call rota out of date, so escalation reaches nobody. | ISO 45001 cl.8.2 | Maintain and test the rota; an escalation route that reaches a former employee is not a route. |
| Lone entry into a permit-required confined space. | 1910.146 | Prohibited; an attendant is mandatory regardless of the space's apparent condition. |
| Assessment not reviewed after a staffing reduction created new lone working. | ISO 45001 cl.6.1.2 | Staffing changes create lone working silently; treat them as a review trigger. |
| Workers not consulted about which situations feel unsafe. | ISO 45001 cl.5.4 | Ask them; they know which visits and which hours carry the risk. |
Worked case
Case in point: the call that reached an empty office
A facilities team introduced a lone worker app with check-in intervals and automatic escalation. It was configured correctly, workers used it, and the arrangement was documented in the assessment. Escalation on a missed check-in routed to the duty manager's number.
The arrangement was tested during a working day and performed as designed. Eighteen months later an engineer working alone on a Sunday evening had a fall and missed a check-in. The escalation fired correctly and dialled a desk phone in an office that was empty at weekends, because the number in the configuration was the duty manager's landline rather than the on-call mobile.
The engineer was found by a cleaner the following morning. The system worked exactly as configured; nobody had ever tested it at a time when the configuration mattered.
Definitions
Definitions and key terms
- Lone working
- Working without close or direct supervision, including where colleagues are present but out of sight and earshot.
- Check-in interval
- The period between confirmations that a lone worker is safe, set from the severity and speed of the credible hazards.
- Escalation trigger
- The automatic action taken when a check-in is missed, which must not depend on a person noticing.
- Time to discovery
- How long before anyone knows something has happened, which is the survival factor for injury or medical emergency while alone.
- Workplace violence prevention plan
- A written plan required in California under Labor Code 6401.9, with prescribed content, training and a violent incident log.
- Violent incident log
- A record of every workplace violence incident with defined fields, retained five years in California, viewable by employees on request.
- Dynamic risk assessment
- On-the-spot reassessment when conditions change during a visit or task, supplementing the written assessment.
- Partial lone working
- Periods during an otherwise staffed shift when someone is effectively alone: breaks, handovers, or working in a separate area.
FAQ
Frequently asked questions
What is the first question in a lone working assessment?+
Why the work is done alone. Necessity, scheduling, cost, or because nobody has examined it. Where the answer is anything other than necessity, the assessment has identified a control that removes the exposure rather than managing it, and that sits above every device and check-in arrangement in the hierarchy.
What makes a check-in system work?+
Automatic escalation. Any arrangement depending on a colleague noticing that a call did not come fails during handovers, holidays and busy periods, which are the conditions under which lone working increases. The escalation should fire on its own, reach a named role rather than a person, and specify what that role does.
How should we test it?+
By deliberately missing a check-in at a time that matters. Testing during office hours confirms the technology and nothing about the human chain. Testing at 2am on a Sunday reliably finds the out-of-date rota, the number that diverts to an empty office, or the person on call with no authority to send anyone.
Does workplace violence legislation affect lone working?+
Increasingly. California's SB 553, in force since 1 July 2024 under Labor Code 6401.9, requires most employers with any California location to maintain a written workplace violence prevention plan, a violent incident log retained five years, annual training and post-incident investigation. Cal/OSHA was directed to propose a general industry standard by December 2025 with adoption due by the end of 2026, and other states have introduced their own requirements.
Are colleagues on site enough?+
Not necessarily. The test is whether help would actually arrive, not whether anyone else is in the building. Someone working in a plant room while colleagues are two floors away and cannot hear a shout is lone working in every respect that matters, and this partial category is the one most often missed in assessments.
The agents
What the agents do with it
The assessment is short. What fails is the escalation nobody tested and the staffing change that created lone working silently.
Holds the assessment against tasks and hours, records the escalation arrangement, and prompts testing outside normal working hours.
Watches staffing and rota changes for newly created lone working, which appears without anyone deciding to create it.
Connects aggression and violence reporting to welfare follow-up, since lone workers report less and need the route to be easy.
Covers contractors working alone on your site, whose escalation frequently routes to their employer rather than to anyone present.
This template lives in KnowSafe — safety and compliance. Incidents, hazards, permits, inspections and the critical controls behind them.
Meet KnowSafe→Sources
Sources
- ISO 45001:2018 clauses 6.1.2, 8.1.2 and 8.2
- HSE INDG73, protecting lone workers (GB)
- California Labor Code section 6401.9, workplace violence prevention, in force 1 July 2024
- 29 CFR 1910.146, permit-required confined spaces, OSHA
- OSH Act Section 5(a)(1), General Duty Clause (US)