Workers can be seriously injured as a result of hazards involving the construction of trenches.
A trench is an excavation that is deeper than it is wide. Generally, a trench is excavated to install or repair underground utilities such as sewers, electricity, watermains, natural gas and telecommunications and to construct foundations for buildings or other structures.
Trenches can be dangerous due to their depth and relatively narrow opening that can limit escape in an emergency. Workers can also be at risk due to widely varying soil types, unstable ground conditions and high water content.
In July and August 2015, the Ministry of Labour conducted a safety blitz focusing on hazards involving the construction of trenches. They visited construction projects across Ontario where trenches were being excavated.
Construction inspectors checked on compliance with the Occupational Health and Safety Act (OHSA) and its regulations. They checked for safety issues involving:
The blitz’s goals were to:
In July and August 2015, ministry inspectors conducted 994 field visits to 862 workplaces and issued 1,683 orders under the OHSA and Regulations for Construction Projects. This included 151 stop work orders. Some of the workplaces were visited more than once.
Of the orders:
Of those orders, four frequently issued trench-related orders under the Regulations for Construction Projects involved a failure of employers to ensure:
Inspection blitzes are part of the province’s Safe at Work Ontario compliance strategy. They are announced to the sector by the ministry in advance, although individual workplaces are not identified in advance. Results are posted on the ministry’s website. The blitzes raise awareness of workplace hazards and are intended to promote compliance with the OHSA and its regulations.
Inspectors’ findings may impact the frequency and level of future inspections of individual workplaces. Inspectors may also refer employers to health and safety associations for compliance assistance and health and safety-related training.
Inspectors visited construction projects where trenches were being excavated.
In particular, ministry inspectors visited construction projects:
Inspectors focused on the following key priorities:
|Number of workplaces visited||862|
|Stop work orders||151|
|Orders and requirements per workplace visited||1.95|
|Orders and requirement per visit||1.69|
Requirements and stop work orders are part of the total orders issued
Trenching incidents continue to be an issue at Ontario construction projects.
Of the 1,683 total orders issued during the blitz:
|Reason for order||Number of orders||Percentage of total  orders|
|Excavation safety (Sections 222 to 242)||195||11.59%|
|Registration and notices (Sections 5 to 6)||147||8.73%|
|Fall protection hazards (Section 26)||143||8.50%|
|Personal protective equipment (Sections 21 to 25)||123||7.31%|
|Access and egress to work areas (Sections 70 to 84)||108||6.42%|
|Emergency procedures (Section 17)||95||5.64%|
|Housekeeping concerns (Sections 35 to 48)||86||5.11%|
|Traffic protection (Sections 67 to 69)||75||4.46%|
|Construction equipment hazards (Sections 93 to 116)||70||4.16%|
|Fire safety (Sections 52 to 55)||40||2.38%|
The most frequently issued orders during this blitz were for excavation-related Sections 222 to 242 of the Regulations for Construction Projects. Almost 12 percent of the orders issued during the blitz concerned these sections.
Other frequently issued orders under the Regulations for Construction Projects were related to the excavation work taking place and included the following contraventions:
About 98 per cent of orders in the 2015 trenching blitz were issued to constructors or employers for non compliance with OHSA and the Regulations for Construction Projects.
During the blitz, 345 orders were issued under the OHSA. Of those, 151 (45 per cent) were stop work orders issued in situations where non compliance posed an immediate risk to the health and safety of workers.
The results show that focusing enforcement on the internal responsibility system continues to be a priority for constructors and employers and is a key to workplace health and safety in Ontario.
During a field visit, inspectors continue to encourage and assist all workplace parties, workers, supervisors, employers and constructors, to work together to keep the workplace safe and ensure compliance with the health and safety laws. During the trenching blitz, workplace parties were encouraged to work together to identify and control hazards involving the excavation of trenches.
The results of this blitz verify the need to continue focused enforcement activity in the above-noted areas.
Inspectors will continue to focus on trenching hazards that may put workers at risk of injury.
For more information on identifying, preventing and controlling these hazards, please contact Ministry of Labor safety partners.