Job Hazard Analysis and Risk Assessment

What a Job Hazard Analysis Is

A Job Hazard Analysis (JHA) is a documented, step-by-step examination of a task that identifies the hazards in each step and specifies the controls needed before work begins. You will see three names for essentially the same tool, and the STSC uses them interchangeably:

• JHA – Job Hazard Analysis (OSHA's preferred term, OSHA Publication 3071).
• JSA – Job Safety Analysis (older industry term, identical method).
• AHA – Activity Hazard Analysis (used on federal/USACE EM 385-1-1 projects).

The single most tested idea is the purpose: a JHA exists to prevent injuries through pre-task planning. It is not a tool to assign blame for past incidents, to document a job for insurance, or to track productivity. Expect a distractor-heavy question where three options are plausible-sounding paperwork uses and only one says "break a task into steps, identify hazards, and specify controls."

The Three-Column Structure

Every JHA is built on three columns. Memorize the order – the exam tests it directly.

A classic trap: a step is not a hazard. "Climb the ladder" is a step; "fall from height" is the hazard; "maintain three points of contact and tie off above 6 feet" is the control. Mixing these up is the most common error candidates make.

How to Build a JHA – Step by Step

1. Select the job. You cannot analyze everything, so prioritize (see below).
2. Involve the worker. The person who does the task knows its real hazards; OSHA stresses employee participation.
3. Break the job into steps. Keep steps broad enough to be useful but narrow enough that each has identifiable hazards – typically not more than about ten steps.
4. Identify hazards in each step. Ask what can strike, crush, cut, burn, shock, or expose the worker, and what energy sources are present.
5. Develop controls using the hierarchy of controls (elimination first, PPE last).
6. Review and revise after any incident, near-miss, process change, or new equipment.

Prioritizing Which Jobs to Analyze

You will be asked which task gets a JHA first. OSHA Publication 3071 lists the priority order, and the STSC mirrors it:

• Jobs with the highest injury or illness rates.
• Jobs with the potential for severe or fatal injury – anything touching the Fatal Four (falls, struck-by, caught-in/between, electrocution).
• Jobs where one simple human error could cause a severe injury.
• New jobs, and jobs that have changed in process, equipment, or materials.
• Complex jobs that require written instructions.

A scenario question may describe four tasks and ask which to analyze first; choose the one with the greatest combination of severity and likelihood – usually the fall or trenching task.

Risk Assessment and the Risk Matrix

Risk assessment turns a list of hazards into a ranked list of priorities. The core relationship the STSC expects you to know:

Risk = Severity × Probability

Severity is how badly someone could be hurt (first aid → recordable → lost time → fatality). Probability is how likely the exposure is to cause harm. A risk matrix plots these on a grid – commonly a 5×5 – and produces a Risk Priority Number or a color band (green/low, yellow/moderate, red/high). High-risk cells must be controlled before work proceeds.

Key exam points:

• A low-probability but catastrophic hazard (e.g., trench collapse) still rates as high risk because severity is extreme – do not dismiss it as "rare."
• Reducing risk means moving down the hierarchy of controls; residual risk is what remains after controls are applied.
• As Low As Reasonably Practicable (ALARP) describes driving residual risk to the lowest feasible level, not necessarily zero.

Putting It on the Jobsite

The JHA is not a binder document – it drives the daily toolbox talk (also called a tailgate or safety briefing). Each morning the supervisor reviews the JHA for that day's specific work, confirms the controls are in place, and verifies workers understand their roles. Worker involvement in this pre-task planning is consistently identified as the single most effective proactive control on the exam.

Common mistakes the STSC tests:

• Treating the JHA as a one-time document instead of a living tool revised after change or incident.
• Writing controls that simply restate "be careful" rather than naming a specific engineering or administrative control.
• Skipping worker input, which yields hazards that look complete on paper but miss field reality.
• Confusing the JHA (a planning tool) with an incident investigation (a reactive, root-cause tool used after something happens).

JHA, AHA, and the Federal Distinction

On most private jobs the term JHA or JSA is used and the document is informal but written. On federal and military construction governed by the USACE EM 385-1-1 manual, the required form is the Activity Hazard Analysis (AHA), which must be reviewed and accepted by the government representative before that phase of work starts and updated when the scope, conditions, or competent person changes. The method is identical – step, hazard, control – but the AHA also names the competent and qualified persons for the activity, the training required, and the inspection requirements.

The STSC may use any of the three names, so do not be thrown by an unfamiliar acronym; the underlying logic never changes.

Connecting the JHA to Daily Field Tools

The JHA is the parent document; several field tools flow from it. A toolbox talk (tailgate meeting) delivers the JHA content verbally each morning. A pre-task plan or safe task analysis card is the worker-level version a crew fills out at the workface. Stop Work Authority is the backstop: if conditions on the ground no longer match the JHA – a soil change, a weather change, an undocumented utility – any worker can stop the task until the JHA is revisited.

Treating these as a connected system, rather than separate paperwork, is exactly the supervisory mindset the exam rewards: plan the work, then work the plan, and re-plan the moment reality changes.