Western Health & Safety outlines the legal duties of a prime contractor under the Alberta OHS Act and WorkSafeBC regulations. This page explains when a prime is needed, what systems are mandatory, and what records prove compliance. Includes checklists, templates, and hazard coordination tips for multi-employer sites across Edmonton, Calgary, Vancouver, and the BC Interior.

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When a prime is required?

A prime contractor is required when there is more than one employer working at the same construction or oil and gas site. This includes subcontractors, service providers, consultants, or trades. The rules apply in both Alberta and British Columbia, with slight differences in how the requirement is triggered:

In AlbertaA prime contractor is legally required at any construction or oil and gas work site where two or more employers are involved.
The prime may be the owner or a directing contractor, but must be formally designated in writing before work begins.
(Alberta OH&S Act – Section 10)

In British ColumbiaA prime is required when:

• Two or more employers are performing overlapping or adjoining work
• The combined workforce is more than five workers
• The work creates or could create hazards between employers

The owner, or someone hired by the owner to act as prime, must:

• Appoint a qualified coordinator
• Require each employer to name a person responsible for site safety
• Post a site drawing showing layout, first aid, evacuation plans
• Provide a written set of safety procedures

The coordinator must notify all parties of shared hazards and ensure those hazards are controlled throughout the job.

Example: Prime-contractor posting in Edmonton, Calgary, Vancouver, and the BC Interior is often required when trades, equipment operators, and suppliers overlap on active sites.
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Standard Operating Procedure (SOP) for Prime Contractors

Prime contractors should develop and follow a written Standard Operating Procedure (SOP) that outlines how they will meet their coordination, verification, and communication duties on a multi-employer site.An SOP is not the same as a site-specific safety plan. The SOP applies across all projects and explains how the prime fulfills their legal role — not just what the site hazards are.

A strong Prime Contractor SOP includes:

• How the prime is designated and documented
• Steps for assigning a coordinator
• Daily verification procedures
• Hazard notification protocols
• Subcontractor onboarding and training checks
• Emergency plan integration
• Near-miss and incident follow-up
• Document retention standards

Having an SOP helps ensure consistency across multiple sites — and provides a framework for training new coordinators, preparing for COR audits, or responding to inspections.

​Tip: Western Health & Safety can assist in reviewing or developing Prime Contractor SOPs that align with Alberta and BC law.

CALL WHS TODAY FOR A PRIME CONTRACTOR AUDIT

Written designation and posting

The prime contractor must be clearly identified in writing for each specific project. Verbal understanding is not enough. The designation must name the prime, describe the scope of the role, and apply to defined dates and locations.
Acceptable designation records include:

• A signed designation letter
  
• A contract clause that names the prime contractor
  
• A written agreement between the owner and the directing contractor
  

The designation should be kept on site and available for review.
Once designated, the prime contractor must post their name at the work site so all workers and employers know who is responsible for coordination. The posting should be:

• Visible at the main site entrance
  
• Legible from a normal approach distance
  
• Updated if the prime changes
  

Good practice is to photo‑document the posting and retain the image with the project safety file. This provides simple proof that workers and inspectors could identify the prime during active work.
Common gaps seen on sites:

• Prime named in a contract but not posted
  
• Posting removed after mobilization
  
• Prime role assumed but never documented
  

Clear designation and posting are the foundation of the prime contractor system. Without them, coordination duties cannot be shown or enforced.

Cooperation system and named coordinator

The prime contractor must establish a cooperation system that allows multiple employers to work safely at the same site. This system must function before work starts and continue for the full duration of the project.
At the centre of the system is a named coordinator with clear authority.
Named coordinatorThe prime must appoint a coordinator in writing. This person must:

• Have the knowledge and experience to manage site hazards
• Have authority to require corrective action
• Be identified to all employers and workers
• Have a designated alternate for absences

The coordinator’s name and contact details should be included in site documents and posted where workers can see them.
Cooperation system requirementsThe cooperation system should ensure that:

• Employers notify the prime of planned work that may create hazards for others
• Hazards created by one employer are communicated to all affected parties
• Controls remain in place as work changes or progresses
• Conflicting work activities are identified and managed

This is a living system, not a one-time meeting.
Typical tools used

• Regular coordination or toolbox meetings
• Written hazard notifications or bulletins
• Task sequencing and permit controls
• Shared inspection and verification processes

Records that show due diligence

• Written coordinator appointment
• Meeting records or briefings
• Hazard notifications and acknowledgements
• Logs showing follow-up and corrective action

A named coordinator without authority, or a system that exists only on paper, does not meet the intent of prime contractor duties. The system must be active, visible, and verifiable.
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Hazard notification to all parties

The prime contractor must make sure all employers, workers, and service providers on site are informed about hazards that could affect them — especially those created by other employers.
This is a key part of the prime’s coordination role. Notification must happen before hazardous work begins and must be tracked.
What counts as a hazard notification?

• A written bulletin about site-wide hazards (e.g., roof openings, energized equipment, excavation zones)
• A task-specific notice from one employer to others (e.g., hot work, confined space entry, chemical use)
• Verbal briefings at coordination meetings (must be recorded in minutes)

Who needs to be notified?

• All subcontractors
• Workers employed by different companies
• Temporary labour
• Equipment operators
• Visitors or delivery personnel exposed to hazards

How to track and prove it

• Use a hazard bulletin with sign-off lines for all parties
• Keep a distribution log or photo evidence of postings
• Confirm verbal briefings are listed in meeting notes

Example: If roofing work creates a fall hazard near HVAC crews, the prime must notify those crews — and confirm they received it.
Failure to notify can result in overlapping work, preventable incidents, or regulatory orders. Notification isn’t just about communication — it’s about documented coordination.
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Daily verification and corrective action

The prime contractor must verify that work can begin safely each day. This means actively checking that known hazards are controlled, required systems are in place, and any issues from the previous day have been addressed.
This is one of the most commonly missed duties on multi-employer sites — and one of the easiest to prove with a simple log or checklist.
What daily verification meansBefore workers begin their tasks, the prime (or a delegate) must:

• Walk the site or high-risk zones
• Check that controls (barricades, signage, fall protection, etc.) are present and functional
• Confirm that hazards identified the day before have been corrected
• Identify any new or emerging risks
• Log findings and actions taken

Verification is not just visual observation. It includes follow-up on documents, permits, and worker readiness if needed.
Corrective action must be closedIf issues are found — missing guards, uncontrolled access, incomplete signage, etc. — they must be:

• Documented
• Assigned to a responsible party
• Corrected before work begins in that area

Once corrected, the verification log should note the fix and the time it was completed. Delayed or ignored corrections weaken the prime’s due diligence.
How to documentUse a daily verification checklist with these elements:

• Date and time
• Location or zone inspected
• Items checked (can be customized per site)
• Deficiencies noted
• Actions taken
• Signature of verifier or prime delegate

Some sites add photo logs for key areas. Others use laminated checklists on whiteboards with daily wipe-and-fill systems.
What regulators look for

• Is verification documented for each active day?
• Are recurring hazards identified and followed up?
• Do workers or contractors know who verifies and when?
• Can the prime show they acted before an incident — not just after?
  
  

Contractor selection and training checks

Before any contractor is allowed to work on site, the prime contractor must make sure they are qualified for the tasks and trained to perform them safely.
This duty applies to all employers under the prime — including subcontractors, consultants, equipment providers, and temporary labour crews.

Contractor selection (pre-qualification)The prime must screen contractors before allowing them on site. This includes checking:

• Their safety history (e.g., WCB record, past incidents)
• Relevant training and certifications
• Whether they have a safety program and supervisor assigned
• Whether their scope of work creates specific risks (e.g., electrical, fall hazard, confined space)

Use the contractor pre-qualification tool to document this review.
Tip: Pre-qualification should be completed before contracts are finalized — not at the job trailer on Day 1.

Training verification before access
The prime must confirm that workers have the required training for their assigned tasks. This includes:

• Fall protection
• WHMIS
• Equipment-specific tickets (e.g., aerial lift, forklift)
• Site orientations
• Any additional training required by permits or the Site Specific Safety Management Plan

Records to keep:

• Copies of certificates or tickets
• Worker training matrix (list by name and task)
• Sign-in logs for orientation
• Verification checklist per contractor

Common issues:

• Workers arrive without proof of training
• Generic training substituted for task-specific requirements
• Subcontractor assumes responsibility — but prime can’t show they checked

Due diligence proof
To demonstrate compliance, the prime should be able to show:

• When each contractor was reviewed and approved
• Who reviewed their documents
• What training was confirmed before access
• What follow-up was done if gaps were found

Training and selection aren’t just paperwork — they are part of the prime contractor’s legal control system.
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Emergency response and rescue readiness

Every multi-employer site must have an emergency response plan (ERP) that is known, available, and ready to use. The prime contractor is responsible for making sure this plan is developed, maintained, and communicated to everyone on site. This includes contractors, workers, visitors, and suppliers — not just the prime’s own crew.
What the ERP must include
The emergency plan should cover:

• First aid coverage and contact info
• Emergency transportation (e.g., vehicle, stretcher, map to hospital)
• Muster point or evacuation station
• Site layout showing access and escape routes
• After-hours response plan
• Rescue procedures for high-risk tasks (e.g., fall arrest, confined space)

The ERP must be based on the actual hazards and layout of the site, not copied from a different job.
How to communicate it

• Provide ERP during site orientation
• Post site drawings and ERP near the sign-in point and lunchroom
• Include ERP info on daily toolbox talks or tailgate meetings
• Brief any new subcontractor or visitor before they start

Photos of posted plans and sign-off logs from briefings are simple proof of communication.
After-hours and high-risk work
If work is done outside regular hours — evenings, weekends, holidays — the ERP must still apply. The prime must:

• Ensure someone can respond
• Confirm workers can contact help
• Have transportation plans in place if first aid is off-site

Example: If electrical work continues Saturday in Vancouver with no supervisor present, the ERP must identify who is available, how to reach them, and where evacuation staging is located.
Records to keep

• Copy of the current ERP (with version date)
• Site drawing showing first aid and evacuation zones
• Orientation sign-off logs
• Rescue drill records (for high-risk tasks)
• After-hours contact schedule

If the ERP is vague, outdated, or unknown to workers — it will not hold up in an investigation. The plan must be real, reviewed, and ready.
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Near-miss and incident duties

The prime contractor is responsible for ensuring that serious incidents and near-misses are investigated, tracked, and closed. This applies to any event that could — or did — result in injury, equipment damage, or a hazard to other employers.
This duty includes incidents involving subcontractors, visitors, and workers from other companies — not just the prime’s own team.
What is a near-miss?A near-miss is an event where no one is hurt, but something almost went wrong. Examples:

• A tool falls from height near another crew
• A worker enters a hazardous area without proper PPE
• A fall arrest system is activated but prevents injury
• A load shifts during lifting, narrowly avoiding collapse

These are not minor — they are missed accidents and must be taken seriously.
What the prime must do

1. Investigate the incident or near-miss
   • Identify the root cause (e.g., system failure, procedure gap, missed control)
   • Involve affected parties, including subcontractors
2. Assign corrective actions
   • Address immediate hazards
   • Improve procedures or training if needed
   • Update the Site Specific Safety Management Plan or site procedures if applicable
3. Share findings
   • Distribute learnings to all site employers
   • Use toolbox talks or coordination meetings to brief crews
   • Keep proof of communication
4. Track follow-up
   • Confirm corrective actions were completed
   • Log dates, responsible parties, and verification

Records to keep

• Completed investigation reports (near-miss or incident)
• Corrective action logs
• Briefing records (toolbox talks, email distributions)
• Photos or documentation of fixes
• Follow-up verification (signed or time-stamped)

Common issues to avoid

• Ignoring near-misses because “no one was hurt”
• Letting subcontractors handle investigations without oversight
• Failing to share findings with other crews on site
• Not verifying that fixes were completed

Owner and contracting-employer interfaces

Even when a prime contractor is appointed, the owner and contracting employers still have legal duties. These roles are connected — not separate. The success of the prime contractor system depends on how clearly responsibilities are shared, documented, and followed.
Owner responsibilities
In both Alberta and BC, the owner of the work site must:

• Designate the prime contractor in writing
• Ensure coordination of health and safety takes place
• Not interfere with the prime’s systems or decisions once designated
• Owners should be auditing the prime to ensure their system is functional and not get involved with the site activties

If the owner retains control over parts of the work (like permitting, utilities, or overlapping trades), they must still coordinate those activities with the prime.
Proof to keep:

• Signed designation letter or contract
• Email or letter of confirmation
• Site maps or schedules showing retained areas of control
• Safety meeting attendance if the owner participates

Contracting employer responsibilities 
Contracting employers (e.g., subcontractors, service providers) must:

• Inform the prime before starting any work that could create a hazard for others
• Provide a contact person responsible for site safety
• Participate in coordination systems (e.g., meetings, hazard notifications, inspections)
• Follow the prime’s safety procedures while on site

If an employer starts work without advising the prime, or performs high-risk tasks outside the system (like hot work, excavation, or confined space entry), the prime may still be held responsible.
🔹 Interface best practices

• Use written scopes of work with identified hazards
• Include safety obligations in subcontracts
• Require all employers to submit site-specific safety plans or procedures
• Maintain a contact list of safety leads for each employer
• Log all coordination actions (briefings, responses, follow-up)

Example: On a Calgary site, the owner may retain responsibility for site utilities. The prime must coordinate trenching work with them. On a Vancouver high-rise, contracting employers must notify the prime before using suspended access or rooftop equipment.

Owner interference: what to avoid

Once an owner has designated a prime contractor, they must allow the prime to control and coordinate health and safety on the site. If the owner starts giving direction to workers or subcontractors, or begins auditing subcontractors directly, this can be seen as interference — and may shift legal responsibility back to the owner. This is especially risky when the owner:

• Has a site representative walking the project daily
• Performs safety inspections on subcontractor crews
• Enforces their own internal safe work procedures on site
• Stops work or gives direction without going through the prime

While it’s appropriate for owners to monitor outcomes, they must not insert themselves into the prime’s chain of command.

Owner interference: what to avoid
Once an owner has designated a prime contractor, they must allow the prime to control and coordinate health and safety on the site. If the owner starts giving direction to workers or subcontractors, or begins auditing subcontractors directly, this can be seen as interference — and may shift legal responsibility back to the owner.
This is especially risky when the owner:

• Has a site representative walking the project daily
• Performs safety inspections on subcontractor crews
• Enforces their own internal safe work procedures on site
• Stops work or gives direction without going through the prime

While it’s appropriate for owners to monitor outcomes, they must not insert themselves into the prime’s chain of command.

Acceptable monitoring (non-interference)
✅ Reviewing the prime’s daily verification records
✅ Requesting summary updates from the safety coordinator
✅ Attending site coordination meetings as an observer
✅ Auditing the prime’s system (not individual subcontractor performance)
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Example: The owner reviews whether the prime is conducting toolbox talks, but does not approach a subcontractor directly to check fall protection gear.

Interference examples (to avoid)
🚫 Conducting surprise safety audits on subcontractors
🚫 Directing a subcontractor to change equipment or method
🚫 Enforcing owner corporate policies on-site instead of those approved by the prime
🚫 Creating a second reporting chain that bypasses the prime contractor

Example 1:
An owner safety advisor walks a site in Calgary and instructs a subcontractor to change their scaffold tie-ins. This bypasses the prime’s authority and creates confusion — especially if the subcontractor follows the owner’s instruction instead of the site Site Specific Safety Management System.

Example 2:
On a Vancouver project, the owner’s rep insists on applying their corporate confined space policy to a subcontractor, even though the prime already has a written and permitted system in place. This creates dual systems — and liability risk.
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Downloads and checklists

✅ 1. Prime Contractor Duties Checklist (10-Point Core)
✅ 2. Daily Verification Checklist
✅ 3. Contractor Pre-Qualification Checklist
✅ 4. Owner System Review Checklist

Frequently Asked Questions

Q: When must an Alberta work site have a prime contractor?

A: When two or more employers are involved at a construction or oil and gas work site.

Q: Is a prime required to be on site all day?

A: No. What’s required is a system and daily verification that shows the prime is in control of health and safety.

Q: What documents show due diligence?

A: Designation letter, posted signage photo, safety plan, hazard bulletins with sign-off, training matrix, daily checklists, and near-miss records.
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Final Notes for Prime Contractors and Owners

Coordinating a multi-employer work site carries serious legal duties — but with the right system, tools, and documentation, compliance can be straightforward.
Whether you're acting as a prime contractor or designating one, the key is to ensure that responsibilities are clear, active, and verifiable each day.
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A functioning system is not just paperwork — it's posted, shared, followed, and updated as site conditions change.

Western Health & Safety provides:

• Prime contractor system reviews
  
• SOP and documentation support
  
• CIH-led audits for multi-employer coordination
  
• Templates aligned with Alberta OHS and WorkSafeBC standards
  

📍 Offices in Calgary and service throughout Alberta & BC
📧 [email protected]
📞 403-241-6889

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