WORKING ALONE ON CONSTRUCTION SITES — ONTARIO SAFETY REQUIREMENTS

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Working alone on a construction site is more common than many people realize. A plumber finishing rough-ins on a Saturday. An electrician pulling wire in a unit while the rest of the crew is on another floor. A site supervisor doing a weekend inspection. A subcontractor showing up early to get a head start before the general contractor's crew arrives. In each of these situations, a worker is alone — and if something goes wrong, there is no one there to help, call for assistance, or even notice that something has happened.

Ontario does not have a single standalone regulation titled "Working Alone." Instead, the obligations arise from the general duty provisions of the Occupational Health and Safety Act (OHSA) and specific requirements in Ontario Regulation 213/91 (Construction Projects). Understanding these obligations is critical for construction employers and supervisors.

What Counts as Working Alone?

A worker is considered to be working alone when they are the only worker for that employer at a workplace and are not able to be seen or heard by another person — or when assistance is not readily available in the event of an injury, illness, or emergency. On a large construction project, a worker can effectively be "alone" even if other trades are on site, if those other workers are in a different building, on a different floor, or otherwise unable to see, hear, or assist the worker.

Common working alone scenarios on construction sites include:

• After-hours and weekend work — workers returning to complete tasks outside of normal working hours when no other workers are on site
• Remote areas of large sites — mechanical rooms, upper floors, basements, rooftops, and utility tunnels where a worker may be out of sight and earshot of others
• Small renovation projects — a single worker or two-person crew working in a residential or commercial renovation, where one worker may be alone for portions of the day
• Site security and monitoring — workers performing security rounds or environmental monitoring on otherwise vacant construction sites
• Equipment operation — a single equipment operator on a site during off-hours, such as a crane operator performing maintenance or a loader operator moving material

Hazard Assessment for Solo Work

Before any worker is permitted to work alone on a construction site, the employer must conduct a hazard assessment specific to the solo work situation. This assessment should go beyond the normal job hazard analysis and consider the additional risks created by the absence of other workers. Key factors include:

• Nature of the work — what tasks will the worker be performing? Some tasks carry inherent risks that are significantly amplified when performed alone, such as working at heights, working in confined spaces, or operating heavy equipment.
• Location and accessibility — where on the site will the worker be? Can emergency responders access the location easily? Is the worker visible from a road, adjacent property, or security camera?
• Duration of isolation — how long will the worker be alone? A 30-minute task carries different risk than an 8-hour shift alone on a site.
• Time of day — night work introduces additional hazards including reduced visibility, lower ambient temperatures, and potentially longer emergency response times
• Communication coverage — does the worker have reliable cell phone reception? Are there dead spots on the site? Is there a landline or radio system available?
• Medical history — while employers must respect privacy, a worker with a known medical condition that could result in sudden incapacitation (such as epilepsy or a heart condition) may face additional risk when working alone. Accommodations should be discussed with the worker.
• Environmental hazards — extreme heat or cold, poor air quality, wildlife, or proximity to bodies of water all increase risk for a lone worker

Check-In Procedures and Intervals

When a worker is permitted to work alone, the employer must establish a system of periodic check-ins to verify the worker's safety. The check-in system is the single most important safeguard for a lone worker because it is the mechanism by which a failure to respond triggers an emergency response.

• Scheduled check-in times — the worker and the designated contact person must agree on specific times for check-ins. The interval should be based on the level of risk: higher-risk tasks require more frequent check-ins. A common standard is every 30 minutes for high-risk work and every 1 to 2 hours for lower-risk tasks.
• Method of check-in — phone call, text message, radio call, or app-based check-in. The method should be reliable and documented. Text messages are less reliable than phone calls because a delayed or undelivered text may not trigger a timely response.
• Designated contact person — someone must be specifically assigned to receive the check-ins and to initiate the emergency response if a check-in is missed. This person must be available during the entire period the worker is alone — not in a meeting, not asleep, not on another job site without their phone.
• Missed check-in protocol — the procedure for a missed check-in must be clear and specific. Typically, if a worker misses a scheduled check-in, the contact person attempts to reach the worker by all available means. If contact is not established within a defined time (often 15 minutes), the emergency response is activated — which may include calling 911, sending someone to the site, or both.
• Documentation — every check-in (and every missed check-in) should be logged. This documentation demonstrates due diligence and provides a record for incident investigation if something goes wrong.

Communication Devices

A lone worker must have a reliable means of communication at all times. The choice of device depends on the site conditions:

• Cell phone — the most common option, but only reliable if the site has consistent cellular coverage. Workers in basements, concrete structures, or remote areas may lose signal. Test coverage in the specific work area before relying on a cell phone as the sole communication device.
• Two-way radio — useful on large sites where another person (such as a security guard or supervisor on an adjacent site) is within radio range. Limited by range and terrain.
• Satellite communicator — for remote sites without cellular coverage, satellite-based devices can provide emergency communication. These range from simple SOS beacons to full two-way satellite messengers.
• Lone worker monitoring devices — purpose-built devices that combine GPS tracking, automatic fall detection (using accelerometers), man-down alarms (triggered by extended inactivity), and panic buttons. These devices automatically alert a monitoring centre if the worker falls, becomes motionless, or presses the panic button. They are the gold standard for lone worker protection.

Emergency Response Plans

Every working-alone arrangement must have an emergency response plan that accounts for the specific challenges of reaching and assisting a lone worker. The plan should cover:

• How the alarm is raised — through the check-in system, a panic button, an automatic alert, or the worker calling for help directly
• Who responds — the specific person or persons responsible for responding to an emergency involving the lone worker, including their contact information and expected response time
• Site access — how the responder will access the site. If the site is locked or gated, the responder must have keys, access codes, or a plan to gain entry. Emergency services (fire, ambulance) must also be informed of access points and any obstacles on the route to the worker's location.
• Location information — the exact location of the worker within the site. On a large or multi-building project, knowing that "the electrician is on site" is not enough — the response plan should specify the building, floor, and area where the worker will be.
• First aid and rescue equipment — a first aid kit must be accessible to the worker. For high-risk tasks, additional rescue equipment may be required on site, such as a defibrillator, naloxone kit, or rescue harness.

Employer Obligations

Under the OHSA, employers have a general duty to take every precaution reasonable in the circumstances for the protection of a worker. When that worker is alone, the standard of "reasonable precautions" increases because the consequences of an incident are amplified by the absence of immediate assistance. Specific employer obligations include:

• Conducting the hazard assessment before permitting solo work
• Establishing and enforcing check-in procedures and ensuring the designated contact person is available and responsive
• Providing appropriate communication devices and verifying that they work at the specific work location
• Training workers on the working-alone procedures, the check-in system, and the emergency response plan
• Documenting everything — the hazard assessment, the working-alone plan, check-in logs, and any incidents or near misses
• Reviewing and updating the plan as conditions change — new tasks, new locations, or changes to the site layout may require updates to the working-alone procedures

High-Risk Tasks That Prohibit Solo Work

Some tasks on construction sites are too dangerous to perform alone, regardless of the check-in system or communication devices in place. Ontario Regulation 213/91 and industry best practices identify several tasks that should never be performed by a lone worker:

• Confined space entry — Ontario Regulation 213/91 requires an attendant stationed outside the confined space whenever a worker enters. Solo confined space entry is never permitted.
• Work requiring fall arrest — if a worker is using a fall arrest system, a rescue plan and the means to execute it must be in place before work begins. A lone worker cannot self-rescue from a suspended position after a fall arrest. Therefore, work requiring fall arrest should not be performed alone.
• Energized electrical work — the Ontario Electrical Safety Code and CSA Z462 require a second person to be present when work is performed on or near energized electrical equipment above certain voltage and energy thresholds.
• Crane and hoisting operations — most crane lifts require a signaller in addition to the operator. Critical lifts require additional personnel for rigging, spotting, and traffic control.
• Excavation and trenching — working in or adjacent to excavations involves risks of collapse, engulfment, and atmospheric hazards that require the immediate availability of rescue personnel.
• Demolition — the unpredictable nature of demolition work, including structural collapse, falling debris, and exposure to hazardous materials, makes it unsuitable for solo work.

If a task appears on this list, do not allow a worker to perform it alone — regardless of schedule pressure, convenience, or the worker's willingness. The risk is simply too high, and the inability to mount a prompt rescue makes these tasks incompatible with working alone.

Working alone is sometimes unavoidable on construction projects. When it happens, it must be planned, documented, and monitored. The few minutes it takes to set up a check-in system and verify communication coverage can be the difference between a minor incident and a fatality.