7.3 Hazard Identification & Mitigation

Proactive Hazard Identification

The cornerstone of incident prevention is the ability to identify hazards before they manifest into accidents. The Construction Manager ensures that robust processes are in place to constantly evaluate the changing environment of a construction site.

The Job Hazard Analysis (JHA)

A Job Hazard Analysis (JHA)—also known as a Job Safety Analysis (JSA) or Activity Hazard Analysis (AHA)—is a vital tool for proactive safety. It focuses on the relationship between the worker, the task, the tools, and the work environment.

The JHA process involves three main steps:

1. Break down the job into sequential steps: Define exactly what the worker is going to do, step-by-step.
2. Identify the hazards for each step: Determine what could go wrong. Could the worker fall? Get shocked? Be struck by debris?
3. Determine preventive measures (controls): Using the Hierarchy of Controls, identify exactly how the hazards from Step 2 will be mitigated.

JHAs are typically required from subcontractors before they begin any new phase of work. The CM reviews these to ensure they are comprehensive and align with the overall Site-Specific Safety Plan.

Safety Inspections and Audits

Regular, documented safety inspections are essential. These can range from daily walk-throughs by superintendents to formal weekly audits conducted by dedicated safety personnel or the CM.

• Inspections generally look for immediate physical hazards (e.g., missing guardrails, frayed electrical cords).
• Audits take a deeper dive, evaluating the overall safety system and ensuring that safety procedures (like permit systems for confined space entry) are actually being followed.

Site Logistics and Layout

Hazard mitigation begins before the first shovel hits the ground. Site logistics planning is a fundamental responsibility of the CM and a major factor in site safety.

Effective logistics planning addresses:

• Traffic Control: Separating pedestrian pathways from heavy equipment traffic to prevent "Struck-By" accidents.
• Material Storage: Defining laydown areas to ensure materials are stored safely, preventing them from falling, collapsing, or obstructing emergency access.
• Crane Placement: Determining crane locations to ensure the swing radius avoids public areas, power lines, and other active work zones.
• Emergency Access: Ensuring unobstructed access for fire trucks and ambulances at all times.

Mitigating High-Risk Activities

Certain activities on a construction site pose disproportionate risks and require highly specialized mitigation strategies.

1. Fall Protection (Working at Heights)

As the leading cause of construction fatalities, fall protection requires intense scrutiny. OSHA requires fall protection at 6 feet in construction.

Mitigation relies heavily on the Hierarchy of Controls:

• Passive Systems (Engineering Controls): These require no action from the worker once installed. Examples include standard guardrail systems (top rail at 42 inches, mid-rail, and toeboard) and safety net systems.
• Active Systems (PPE): These require the worker to wear and properly use equipment. The most common is the Personal Fall Arrest System (PFAS), which consists of an anchorage point, a lifeline/lanyard, and a full-body harness. The anchorage point must be capable of supporting 5,000 lbs per worker attached.

2. Excavation and Trenching

Cave-ins are incredibly dangerous, happening rapidly and suffocating victims. Soil weighs over 100 lbs per cubic foot. OSHA requires protective systems for trenches 5 feet or deeper (or less if the Competent Person sees a potential for cave-in).

Mitigation strategies include:

• Sloping or Benching: Cutting the trench walls back at an angle to prevent collapse. The required angle depends on the soil classification (Type A, B, or C).
• Shoring: Installing a support structure (like timber or hydraulic aluminum) against the trench walls to hold the soil back.
• Shielding: Using trench boxes. Shielding does not prevent the trench from collapsing; rather, it protects the workers inside the box if a collapse occurs.

A Competent Person must inspect excavations daily before work begins.

3. Electrical Hazards

Temporary electrical systems on construction sites are prone to damage. Mitigation strategies include:

• Ground-Fault Circuit Interrupters (GFCIs): Mandated for all 120-volt, single-phase, 15- and 20-ampere temporary receptacles. GFCIs detect minor imbalances in current and shut off power in milliseconds, preventing lethal shocks.
• Assured Equipment Grounding Conductor Program (AEGCP): An alternative to GFCIs, requiring rigorous, documented testing of all cords and receptacles.
• Lockout/Tagout (LOTO): Procedures to ensure that electrical systems are de-energized, locked out, and verified to be dead before maintenance or repair work is performed.

Hazard Communication (HazCom)

Workers have the "Right to Know" about the chemical hazards they are exposed to. The OSHA HazCom standard requires employers to:

• Maintain a chemical inventory.
• Ensure all containers are properly labeled with hazard warnings.
• Provide Safety Data Sheets (SDS) (formerly MSDS) for every hazardous chemical on site, ensuring they are readily accessible to workers.
• Train workers on how to handle the chemicals safely.