From September 5, 2022 to November 4, 2022, the Ministry of Labour, Immigration, Training and Skills Development (MLITSD) conducted a health and safety initiative which focused on excavations and utility contacts on construction projects.

We began by focusing on education, outreach and awareness, in partnership with our health and safety associations, to provide training and education to employers. The goal was to help employers comply with the requirements under the Occupational Health and Safety Act (OHSA) and its regulations prior to focused inspections.

Beginning September 5, 2022, we conducted a focused inspection blitz at workplaces to check that employers were complying with the OHSA and its regulations. In particular, inspectors checked that employers were taking appropriate action to assess and deal with hazards for the protection of workers specifically focused on:

  • excavation cave-in prevention
  • precautions concerning underground services
  • safe limits of approach to energized overhead electrical conductors

MLITSD inspectors:

  • conducted 975 field visits with 121 additional field visits with support role activityfootnote 1
  • visited 876 workplaces
  • issued 2,081 orders and requirements, including 259 stop work orders


A recent Coroner’s jury recommendation related to an excavation fatality raised the need for an increase in cave-in/collapse awareness. The recommendation focused on the ministry increasing awareness about the hazard of trench cave-ins.

In addition, during 2019, there were a number of powerline contacts that resulted in worker fatalities. The ministry is working with the utility industry to increase awareness of the powerline contact hazards.

In August 2022, a trench collapse in Ajax resulted in two workers being fatally injured and two other workers being critically injured.

Full report

Workplace inspection initiatives

Inspection initiatives are part of our compliance strategy. We announce to the sector in advance that we will be conducting an initiative, although individual workplaces are not notified in advance. The results of the initiative are typically posted online within 90 days. Inspectors’ findings may impact the number and level of future inspections of individual workplaces.

Inspectors may also refer employers to health and safety associations for compliance assistance and training.

Focus of the initiative

For excavations and utilities, common hazards include:

  • contact with energized overhead electrical conductors
  • cave-ins
  • underground utility service contact
  • falling into the trench or excavation
  • slips, trips, and falls as workers climb on and off equipment, or from inappropriate access and egress methods
  • flooding or water accumulation
  • exposure to a hazardous atmosphere (e.g., gas, vapour, dust, or lack of oxygen)
  • being struck by moving machinery, or by falling or flying objects
  • hazards related to materials handling (e.g., lifting, struck by, crushed between, etc.)

Inspectors checked for:

  • employers having made a full assessment of the area being excavated, including knowing the voltage of overhead power lines if any, arranging for adequate locates and markings, planning the work and assigning the supervisory responsibility to a competent person
  • workers following the procedures established by the employer and carrying out the work in a safe manner

Inspectors focused on the following specific areas:

  • known voltage of overhead power lines when present and precautions taken to keep the minimum required limit of approach from them
  • signs warning of overhead energized electrical conductors where required
  • a competent designated signaller was in place to warn equipment operators when working near overhead, energized, electrical conductors to ensure machinery remained clear of hazard
  • a barrier at least 1.1 m high was installed at the top of an excavation that was deeper than 2.4 m
  • underground services were accurately located and marked
  • hazardous services were shut off and disconnected prior to excavation
  • adequate shoring or sloping, including for excavation walls were present in accordance to the soil type and as prescribed by an engineer where required
  • adequate support for live or active infrastructure to prevent release of uncontrolled energy
  • no material or equipment was stored too close to the excavation walls so that to affect their stability
  • adequate means of access to or egress from the excavation were provided within the support structure of the excavation
  • no work was performed in a trench, unless another worker was working above ground in close proximity to the trench or to its means of access
  • excavation walls were stripped of loose rocks or material that may slide, roll or fall upon a worker, and supported by wire mesh where necessary
  • precautions specified in writing by a professional engineer were being followed to ensure the stability of the excavation walls and the integrity of adjacent structures or buildings
  • excavations were kept reasonably free of water
  • workers in an excavation were not exposed to atmospheric hazards or noxious fumes
  • equipment used in or around the excavation was used safely and in accordance to its manufacturer’s instructions
  • emergency procedures for the rescue of workers were in place and being followed

Inspectors took appropriate action if contraventions were found under the OHSA or its regulations. This included issuing the appropriate order to the contraveners, including stop work orders, to have them comply with the legal requirements

Inspection activity summary

Visits to workplaces

  • 975 field visits with 121 support role activity
  • 876 workplaces visited
  • 2,081 orders and requirements issued
    • 1,998 orders issued for contraventions under the OHSA and its regulations, including 259 stop work orders
    • 83 requirements issued to provide an inspector with workplace information
  • an average of 2.37 orders and requirements issued per workplace visited
  • an average of 2.13 orders and requirements issued per visit

Most frequently issued orders

The most frequently issued OHSA orders and requirements involved:

  • stop work order, clause 57(6)(b): 188 orders or 9.03% of the total orders and requirements issued during the initiative
  • stop work order, clause 57(6)(a): 73 orders or 3.51% of the total orders and requirements issued during the initiative
  • requirement to produce drawings, specifications, licence, document, record or report, to be inspected, examined and copied, clause 54(1)(c): 64 requirements or 3.08% of the total orders and requirements issued during the initiative

A total of 1,686 orders were issued under the Regulation for Construction Projects (O. Reg. 213/91).

The following were the most issued orders:

  • worker to wear protective clothing, equipment or devices as necessary to protect the worker, subsection 22(1): 171 orders or 8.22% of the total orders and requirements issued during the initiative
  • constructor to file a notice of project with the closest ministry office for the project, subsection 6(3): 74 orders or 3.55% of the total orders and requirements issued during the initiative
  • adequate support for the walls of an excavation, subsection 234(1): 73 orders or 3.51% of the total orders and requirements issued during the initiative

The following orders issued under the construction regulation were the most related to the stop work orders issued under OHSA:

  • adequate support for the walls of an excavation, subsection 234(1): 50 orders or 2.4% of the total orders and requirements issued during the initiative
  • handrails on the open end of each side of stairs landing, clause 77(2)(e): 23 orders or 1.1% of the total orders and requirements issued during the initiative
  • guardrails on the open side of a floor, roof or work surface, subsection 26.3(1): 21 orders or 1% of the total orders and requirements issued during the initiative
  • to keep clear of equipment and material, a level area of at least one meter from the edge of the wall of an excavation, subsection 233(1): 19 orders or 0.9% of the total orders and requirements issued during the initiative


Common issues

  • Not providing adequate support to the walls of an excavation continues to be a very high hazard that can result in serious outcomes.
  • Workers continue to be exposed to the potential hazard of excavation walls collapsing or material falling from the excavation walls.
  • Workers continue to be exposed to personal injury, namely falling from heights and other bodily injury due to the lack of adequate engineered controls for fall protection (for example guardrails, handrails) or the use of personal protective devices to control the specific hazards to which workers may be exposed.

Planning Precautionary Measures

  • Heightened awareness of any hazard can bring change. All workplaces parties must continue to be diligent and not allow complacency to creep into their daily routines.
  • The risk of excavation walls collapsing can be prevented by raising awareness and taking proper precautions, namely:
    • knowing the type of soil where the excavation is dug and using the corresponding adequate support system, sloping, or a combination thereof, depending on the soil type and engineering feedback where needed
    • making sure that equipment, material and excavated soil are kept at least at one meter from the edge of the wall of the excavation
    • making sure that stored material is kept at least at 1.8 metres from the edge of the wall of the excavation

Conclusion and next steps

Ministry inspectors will continue to pay attention to the hazards to which workers may be exposed in or about an excavation, especially those that may result in:

  • the collapse of the excavation walls
  • contacting live electrical overhead wires
  • falling
  • being run over or crushed by equipment
  • succumbing to atmospheric hazards due to lack of oxygen or emission of noxious products such as exhaust gases or fumes

The results of the initiative confirm our need to continue to focus on adequate training, assessment of hazards, job planning, and a functional internal responsibility system in the workplace.

Help for employers

A key to workplace health and safety in Ontario is the Internal Responsibility System (IRS). Workplace parties are encouraged to work together to identify and control all hazards.

Please contact our health and safety partners for more guidance on compliance for construction projects

Learn more about achieving compliance on construction projects with respect to: