Job Hazard Analysis and Pre-Task Planning

Job Hazard Analysis and Pre-Task Planning

A job hazard analysis (JHA) — also called a job safety analysis (JSA) — is a structured review of a task before it is performed. The method is simple: define the job, break it into logical steps, identify the hazard at each step, choose a control, assign responsibility, and communicate the plan. In construction the JHA is only useful when it reflects the work that will actually happen that day. Generic lines like "be careful," "use PPE," or "watch for equipment" give no direction on a changing jobsite and are a common exam distractor for the weak answer.

What a useful JHA contains

Expect a JHA to answer who, what, where, when, and how. It should identify the task, location, crew, equipment, materials, sequence, permits, required inspections, and emergency considerations, plus nearby trades and any public or owner exposure. A JHA for hot work near stored combustibles, for instance, should specify a fire watch maintained for at least 30 minutes after work ends, extinguisher placement, combustible removal or shielding within 35 feet, and any atmospheric testing — not just "use a fire extinguisher."

Breaking the task into steps

The breakdown must be detailed enough to reveal changing hazards yet short enough that the crew still uses it. For a concrete-saw cutting task, useful steps are: mobilize saw and water source; establish the exclusion zone; inspect blade, guard, and power source; perform wet cutting; manage slurry; clean the area. Each step carries different energy. Mobilization brings material handling and struck-by exposure; cutting brings respirable crystalline silica, noise above 85 dBA, flying particles, electrical shock, and blade contact; cleanup brings slips, slurry disposal, and continued dust if dry sweeping is allowed.

The point is alignment: hearing protection does not control blade contact, wet methods do not control pedestrian entry, and a ground-fault circuit interrupter (GFCI) does not control silica. The CHST checks for that step-to-control match when reviewing any JHA.

Pre-task planning in construction

Pre-task planning is the daily or shift-level application of hazard analysis, and it must reflect current conditions rather than the original plan. Weather, lighting, congestion, crane picks, spoil placement, energized systems, deliveries, and schedule slips all shift the risk profile. A task that was safe yesterday may need new controls today because another trade pulled a guardrail, an opening was cut, a scaffold tag changed color, or wind made material handling unsafe.

A good pre-task discussion is short, specific, and interactive: the supervisor reviews steps, known hazards, controls, stop-work triggers, signals, and emergency actions, and asks the crew, "What changed, and what could go wrong?" The CHST does not run every meeting but coaches supervisors toward those questions and confirms the crew understands the critical controls.

CHST review and coaching

Treat JHA review as field verification, not a pass/fail paperwork check. Strong review questions:

• Does the JHA match the actual task and the actual work area?
• Are severe hazards captured even for brief exposures?
• Are controls listed in hierarchy order where feasible?
• Are adjacent workers and trades considered?
• Are inspection points scheduled before the exposure begins?
• Are stop-work conditions clear enough that a worker can act alone?

Then compare the written plan to the field. If it says "controlled access zone," is the boundary installed and visible? If it says "spotter," is the spotter dedicated or also running a tool? If it says "wet cutting," is water flowing continuously? If it says "respirator," has selection, medical evaluation, fit testing, and the correct cartridge or filter been handled under the written respiratory program?

Updating the JHA

Update the JHA whenever scope, location, crew, equipment, material, sequence, or environment changes in a way that affects hazards or controls. A crew moving from grade-level assembly to elevated installation gains a fall exposure. A sub switching from battery tools to fuel-powered equipment inside an enclosed area introduces carbon monoxide and ventilation concerns. A revised lift path creates new overhead and interface hazards. The update need not be elaborate, but it must be meaningful.

A worked JHA example

Take a task to install a 200-pound rooftop curb using a material hoist. Step one, stage materials at grade: hazards are manual handling and pinch points; controls are mechanical lifting aids and gloves. Step two, hoist the curb: hazards are dropped load and struck-by; controls are a tagged hoist within rating, a barricaded landing zone, tag lines, and a signal person. Step three, work at the roof edge: the hazard is a fall over 6 feet; the control is a guardrail or a tied-off personal fall-arrest system with rescue planned.

Step four, set and fasten: hazards are caught-between and powder-actuated tool use; controls are operator certification and an exclusion zone. Each step exposes a different energy, and each control maps to that specific energy — the signature of a strong JHA.

Common exam traps

Exam items often offer a JHA that lists hazards but pairs them with mismatched controls — "silica dust" answered with "hearing protection," or "struck-by from a swinging load" answered with "a daily stretch." Pick the option where the control actually intercepts the named hazard. Another trap treats a completed signature page as proof of safety; the better answer always verifies that the listed control is physically present before exposure begins. For both the exam and the field, remember that a signed form with vague controls is weak; a specific plan the crew understands and follows is strong.