Ontario Construction Site Safety Signs — OHSA Requirements, Sizes & Placement

Ontario construction sites are among the most heavily regulated workplaces in the province. The Construction Projects Regulation, O. Reg. 213/91 under the Occupational Health and Safety Act, R.S.O. 1990, c. O.1 (OHSA) sets detailed signage requirements for every construction project. Ministry of Labour, Immigration, Training and Skills Development (MLITSD) inspectors conduct thousands of construction site inspections annually, and signage deficiencies are among the most frequently cited violations. Fines can reach $1,500,000 for corporations and 12 months imprisonment for individuals.

This guide covers every sign required on Ontario construction projects, from the project information board to hazard-specific warning signs.

Project Information Sign (O. Reg. 213/91, Section 6)

The most fundamental sign requirement — Section 6 of O. Reg. 213/91 requires a project information sign at every construction project before work begins:

• Location: Prominently displayed at every entrance to the construction site
• Size: Large enough to be read from the road or public way — minimum 1.2 m x 1.2 m (4 ft x 4 ft) recommended
• Content must include:
• Name, address, and telephone number of the project owner
• Name, address, and telephone number of the constructor
• Name, address, and telephone number of the architect or engineer (if applicable)
• Name of the supervisor in charge of the project
• The building permit number (if a building permit has been issued)
• Durability: Must be weather-resistant and maintained in legible condition for the duration of the project
• Timing: Must be posted before any work commences on the site

Personal Protective Equipment Signs

Under O. Reg. 213/91, Sections 21-27, PPE-related signs are required:

Mandatory PPE at Site Entrance

• "CONSTRUCTION SITE — HARD HAT AREA" at every entrance to the construction zone
• "SAFETY BOOTS REQUIRED" — CSA-approved footwear signs
• "HIGH-VISIBILITY VEST REQUIRED" — where vehicle traffic is present
• "SAFETY GLASSES REQUIRED" — in areas where eye hazards exist
• "HEARING PROTECTION REQUIRED" — where noise levels exceed 85 dBA (O. Reg. 381/15, Noise Regulation)
• Format: ISO 7010 standard — blue circular signs with white PPE pictograms

Fall Protection Signs

• "DANGER — FALL HAZARD" at any open edge, floor opening, or elevated work area above 2.4 metres (construction) or 3.0 metres (general industry)
• "GUARDRAILS REQUIRED" or "FALL ARREST REQUIRED" in areas where fall protection is mandatory
• "DANGER — OPEN HOLE" at all floor openings, stairwells under construction, and shaft openings
• Floor openings must also be physically guarded or covered — signage alone is not sufficient under O. Reg. 213/91, Section 26.3

Excavation and Trenching Signs

Under O. Reg. 213/91, Sections 222-242:

• "DANGER — EXCAVATION" or "DANGER — OPEN TRENCH" posted at each approach to the excavation
• "NO ENTRY" — where excavation entry is restricted to authorized workers only
• Underground utility warning: "CAUTION — UNDERGROUND UTILITIES" where locates have identified buried services
• Shoring requirements: Excavations over 1.2 metres deep in certain soil conditions must post the shoring system type and engineer's design
• Barricading: Physical barriers with warning signs are required around all excavations accessible to the public
• Traffic control: Where excavations are near roadways, TC signs per Ontario Traffic Manual Book 7 are required

Crane and Hoisting Signs

Under O. Reg. 213/91, Sections 150-170:

• "DANGER — OVERHEAD CRANE" or "DANGER — OVERHEAD LOADS" in all areas where cranes operate
• Rated capacity: The crane's rated capacity chart must be posted in the operator's cab and be legible from the ground
• "DO NOT STAND UNDER SUSPENDED LOADS" — posted in rigging areas and along common crane paths
• Powerline proximity: "DANGER — OVERHEAD POWERLINES — MINIMUM CLEARANCE [X] METRES" where cranes operate near electrical lines (minimum approach distances per O. Reg. 213/91, Section 188)
• Signal person: "CRANE SIGNALS IN USE" where hand signals are used between operator and signal person
• Swing radius: Barricades and warning signs at the crane's swing radius to prevent worker entry into the crush zone

Electrical Hazard Signs

• "DANGER — HIGH VOLTAGE" on all temporary electrical panels and transformer enclosures
• "DANGER — OVERHEAD POWERLINES" where work occurs near energized conductors
• Lockout/tagout signs: "DANGER — DO NOT OPERATE — LOCKED OUT" tags on all energy isolation points during maintenance
• Ground fault protection: Signs indicating that all temporary power is GFCI-protected per O. Reg. 213/91, Section 195.2
• Clearance distances: Posted at locations where workers may approach energized lines — distances per Table in Section 188

Traffic Control Signs (Ontario Traffic Manual Book 7)

Construction sites affecting public roadways must display traffic control signs per the Ontario Traffic Manual (OTM) Book 7:

• Construction zone ahead: Orange diamond warning signs (TC-1, TC-2 series)
• Reduced speed zone: Regulatory speed reduction signs with "CONSTRUCTION ZONE" tabs
• Lane closure: Arrow boards, channelizing devices, and lane closure signs
• Flagperson ahead: "FLAG PERSON AHEAD" signs at both approaches
• Detour signs: Where public roads are closed, approved detour route signage per MTO standards
• Fines doubled: "FINES DOUBLED IN CONSTRUCTION ZONE" signs are placed by municipalities/MTO
• Reflectivity: All traffic control signs must meet MTO engineering standards for retroreflective sheeting — 3M Diamond Grade or High Intensity Prismatic is the industry standard

Confined Space Signs (O. Reg. 213/91, Section 221)

• "DANGER — CONFINED SPACE — ENTRY BY PERMIT ONLY" at every confined space entry point
• Permit display: The entry permit must be posted at the entry point for the duration of the work
• Rescue plan: "RESCUE EQUIPMENT LOCATED HERE" sign at the rescue equipment station
• Atmospheric testing: "ATMOSPHERIC TESTING REQUIRED BEFORE ENTRY" posted at confined space openings

Asbestos and Hazardous Material Signs

Under O. Reg. 278/05 (Asbestos on Construction Projects):

• Type 1 operations: Warning signs at the work area: "CAUTION — ASBESTOS DUST HAZARD"
• Type 2 operations: Warning signs plus barricading: "DANGER — ASBESTOS — DO NOT ENTER WITHOUT AUTHORIZATION"
• Type 3 operations: Full enclosure signage: "DANGER — ASBESTOS REMOVAL IN PROGRESS — AUTHORIZED PERSONNEL ONLY — RESPIRATOR REQUIRED"
• Lead: "CAUTION — LEAD HAZARD" where lead-containing materials are being disturbed (O. Reg. 490/09)
• Silica: "CAUTION — RESPIRABLE SILICA DUST" where concrete cutting, grinding, or sandblasting occurs

Fire Prevention Signs on Construction Sites

• "NO SMOKING — FLAMMABLE MATERIALS" where flammable liquids, gases, or materials are stored
• Fire extinguisher locations: Signs posted at each fire extinguisher station
• Hot work permit zone: "HOT WORK IN PROGRESS — FIRE WATCH REQUIRED" where welding, cutting, or brazing occurs
• Emergency assembly point: Posted and communicated to all workers during site orientation

Penalties and Enforcement

MLITSD conducts proactive inspection blitzes on Ontario construction sites:

• Corporations: Fines up to $1,500,000 per violation under OHSA Section 66
• Individuals (constructors, supervisors, workers): Fines up to $100,000 and/or 12 months imprisonment
• Stop-work orders: MLITSD can shut down an entire construction project for safety deficiencies including missing signs
• Compliance orders: Written orders with specific deadlines — failure to comply triggers additional penalties
• Constructor liability: The constructor (typically the general contractor) is responsible for overall site signage compliance under OHSA Section 23
• Subcontractor responsibility: Each employer on site is also responsible for signage in their work areas