Guides
Common SST mistakes on construction sites
Updated March 30, 2026
Even well-managed sites see the same errors. Identifying them is the first step to preventing them. Here are the most frequent and what you can do.
Inadequate fall protection
The most fatal mistake: working at height without proper protection, using a harness with no valid anchor, or temporarily removing a guardrail 'just to pass material.' Falls remain the leading cause of construction death.
Task-specific checklists (roofing, scaffolding, height work) help systematize checks before each intervention.
Poor confined-space and lockout management
Entering a manhole, tank, or crawl space without atmospheric assessment is a fatal error. Working on equipment without lockout exposes workers to unexpected restarts.
Training alone is not enough: a pre-entry or pre-work checklist reminds workers of critical steps when routine sets in.
Underestimating 'everyday' risks
A poorly positioned ladder, a damaged extension cord, missing signage in an equipment-reversing zone: these 'ordinary' hazards cause more injuries than dramatic events.
Start-of-shift inspections and daily equipment lists catch these problems before they become incidents.
Insufficient documentation
Failing to document inspections, training, and non-conformities weakens prevention and your record in case of an event. CNESST expects to see evidence of due diligence.
OK Sécurité turns checklist completions into timestamped evidence, exportable as PDFs, organized by team and project.
This article provides common examples for information. Every site has unique risks — consult your prevention program and CNESST for your specific situations.
Related checklists
Checklists to prevent the most common mistakes:
Common questions
- What is the most dangerous mistake?
- Statistically, unprotected falls are the leading cause of construction death in Québec. Confined-space and lockout failures follow closely.
- How to convince a team to change habits?
- Start with the highest-risk tasks and show concrete results. Short, targeted lists are better accepted than bureaucratic systems.
- Inspections take too much time. What can we do?
- A mobile checklist takes 2–5 minutes. Time lost to an accident is measured in days or weeks. Prevention is an investment, not a cost.
- Does OK Sécurité help reduce these errors?
- Yes. Trade and situation checklists cover commonly missed items. Completion history lets you spot trends and adjust training.