How to Master One of the Hardest Parts of the BCSP CHST Exam: Hazard and Risk Identification and Control

Candidates often name Hazard and Risk Identification and Control as the toughest part of the Construction Health and Safety Technician (CHST)® exam. It’s also the biggest. At 36.6% of the exam, it accounts for roughly 73 of the 200 questions, more than any other domain.

Why is it so hard? First, it’s wide: the blueprint lists more than 20 specific hazard categories, from cranes and trenches to radiation and biological hazards. Second, most people’s experience is deep in a few trades and thin in others. A superintendent who has spent years on commercial buildings may rarely think about crane power line clearances or lead in bridge paint. Third, the questions mix recall of specific numbers with judgment about which control is best.

In this guide, we’ll break down what the domain covers, the core concepts and values worth knowing cold, common traps, and a focused study approach.

What Does Hazard and Risk Identification and Control Cover on the CHST Exam?

Domain 1 of the CHST5 Examination Blueprint (effective April 12, 2022) contains 31 knowledge statements and five skill statements. The knowledge statements fall into three groups:

Safety hazards: hot work, electrical, excavations, heights and fall protection, confined spaces, struck-by, mechanized equipment, hoisting and rigging, cranes, material handling and storage, housekeeping, powder-actuated tools, hand and power tools, and concrete work.
Health hazards: asbestos, lead and heavy metals, noise, radiation, silica, chemicals (including the GHS), extreme climates, vibration and impact, and biological hazards.
Cross-cutting topics: safety through design, multi-trade worksites, ergonomics, PPE requirements, and testing equipment.

The five skills tie it together: apply the hierarchy of controls, develop job hazard analyses, prioritize corrective actions, select measuring instruments, and select protective equipment.

What Core Concepts Should You Master?

The Hierarchy of Controls

This is the single most tested idea in the domain. Controls are ranked from most to least effective:

Elimination: Remove the hazard entirely, such as prefabricating a component at ground level so no one works at height.
Substitution: Replace it with something less hazardous, such as a lower-toxicity coating.
Engineering controls: Isolate people from the hazard, such as guardrails, trench boxes, or wet cutting and local exhaust for silica.
Administrative controls: Change how people work, such as procedures, permits, training, signage, and work rotation.
PPE: The last line of defense, such as respirators, hearing protection, and personal fall arrest systems.

Safety through design applies the same logic earlier. The best time to eliminate a hazard is in planning and design, before crews are ever exposed.

Job Hazard Analysis

A JHA breaks a task into steps, identifies the hazards of each step, and assigns controls. Priority usually goes to tasks with a history of injuries, high severity potential, new or changed tasks, and non-routine work. On the exam, a good JHA answer is task-specific and involves the workers who actually do the job.

Key Construction Thresholds (29 CFR 1926)

Many questions rely on numbers from OSHA’s construction standards. These are worth knowing without hesitation:

Fall protection: Required at 6 feet or more above a lower level in most construction work (Subpart M). Scaffolds use a 10-foot trigger (Subpart L).
Guardrails: Top rail at 42 inches, plus or minus 3 inches, able to withstand 200 pounds of force. Midrails sit about halfway, around 21 inches.
Personal fall arrest: Anchorages must support 5,000 pounds per worker attached (or be designed with a safety factor of at least two under a qualified person’s supervision). Free fall is limited to 6 feet.
Ladders: Portable ladder side rails extend at least 3 feet above the landing. Set extension ladders at a 4:1 ratio, meaning the base is one foot out for every four feet of working length.
Excavations: A protective system is required at 5 feet or deeper unless the excavation is entirely in stable rock. Trenches 4 feet or deeper need a means of egress within 25 feet of lateral travel. Keep spoil piles at least 2 feet from the edge.
Soil classification and sloping: Maximum allowable slopes for excavations under 20 feet are 3/4:1 for Type A soil, 1:1 for Type B, and 1 1/2:1 for Type C.
Silica: The permissible exposure limit (PEL) is 50 micrograms per cubic meter as an 8-hour time-weighted average (TWA), with an action level of 25. Table 1 of 1926.1153 lists specified controls for common tasks.
Lead: PEL of 50 micrograms per cubic meter (8-hour TWA) with an action level of 30.
Asbestos: PEL of 0.1 fiber per cubic centimeter (8-hour TWA), with an excursion limit of 1.0 f/cc over 30 minutes.
Cranes near power lines: For lines up to 50 kV, maintain at least 10 feet of clearance.
Confined spaces (Subpart AA): Test the atmosphere in this order: oxygen, then flammables, then toxics. Acceptable oxygen is 19.5% to 23.5%.

Noise Calculations

OSHA’s noise limit is 90 dBA as an 8-hour TWA, with a 5 dB exchange rate. That means allowed time halves for every 5 dB increase: 8 hours at 90 dBA, 4 hours at 95, and 2 hours at 100. Daily dose is the sum of actual exposure time divided by allowed time for each level, times 100. A dose over 100% exceeds the limit. Also remember that decibels add logarithmically: two identical 90 dBA sources combine to about 93 dBA, not 180.

Selecting Instruments and PPE

Match the tool to the hazard: a four-gas meter for confined spaces, a sound level meter or noise dosimeter for noise, air sampling pumps for silica or lead, and a wet-bulb globe temperature (WBGT) reading for heat stress. For PPE, pick based on the specific hazard and verify fit. For example, respirator use requires medical evaluation and fit testing, and a GFCI or an assured equipment grounding conductor program protects workers using cord-and-plug tools.

What Are the Most Common Traps in This Domain?

Jumping to PPE. If an answer eliminates or engineers out the hazard and it’s feasible, it usually beats respirators, harnesses, or hearing protection.
Mixing up trigger heights. Six feet for general construction fall protection, 10 feet for scaffolds, and different rules for ladders. Exam writers know candidates blur these.
Confusing 4 feet and 5 feet in trenches. Four feet triggers the egress requirement. Five feet triggers a protective system.
Using general industry rules. Construction has its own standards in Part 1926, and some values differ from Part 1910.
Treating training as a control that fixes everything. Training is an administrative control. It supports other controls but rarely stands alone as the best answer.
Ignoring the competent person. Many construction standards require a competent person to inspect excavations, scaffolds, and similar work daily and after events such as rainstorms.

How Do You Reason Through a Hazard Control Question?

Consider a question where a crew is laying pipe in a trench 7 feet deep. The competent person has classified the soil as Type B, and a nearby road carries heavy traffic. The question asks what must be in place before workers enter.

Start with the numbers. At 7 feet, the trench is past the 5-foot trigger, so a protective system is required. For Type B soil, sloping must be no steeper than 1:1, but vibration from traffic may indicate the soil could be downgraded, and space along a road is often limited. A shoring system or trench shield designed for the conditions is the stronger answer. Because the trench is deeper than 4 feet, workers also need a ladder or other egress within 25 feet of lateral travel. Answers that focus only on hard hats or a pre-entry briefing miss the core hazard: cave-in.

Now consider a scenario where workers are dry-cutting concrete with a handheld saw, and air sampling shows silica above the PEL. Options include issuing N95 respirators, rotating workers every two hours, switching to a saw with an integrated water delivery system, or posting warning signs.

Water suppression is an engineering control that reduces the silica at the source, and it’s one of the control methods listed in Table 1 of the silica standard. Respirators may still be needed, but the best answer reduces exposure for everyone nearby.

How Does This Domain Connect to the Rest of the CHST Exam?

Domain 2 (Emergency Preparedness, Incident Investigation, and Response): The hazards you identify drive your emergency action plan. A confined space entry needs a rescue plan, and a site with fuel storage needs fire protection and spill response.
Domain 3 (Safety Program Development, Implementation, and Sustainment): Inspections and trend analysis reveal recurring hazards, and site-specific safety plans document the controls you selected.
Domain 4 (Leadership, Communication, and Training): Controls only work if people understand and follow them. Recognizing imminent danger and communicating hazards to a multi-trade crew are listed skills in Domain 4.

How Should You Study Hazard and Risk Identification and Control?

Because this domain is so broad, study it in clusters rather than all at once:

Week 1: Hierarchy of controls, JHAs, and fall protection, including scaffolds and ladders.
Week 2: Excavations, cranes, rigging, and electrical hazards.
Week 3: Health hazards: silica, lead, asbestos, noise, heat, and chemicals under the GHS.
Week 4: Confined spaces, hot work, tools, concrete, and instrument selection, followed by mixed review.

Make a one-page sheet of key thresholds and quiz yourself on it until the numbers come instantly. Then practice applying them in scenarios, because the exam rarely asks for a number on its own.

In Pocket Prep’s BCSP CHST prep, use Build Your Own Quiz to focus on the Hazard and Risk Identification and Control subject, then run Missed Questions to revisit anything you got wrong. Weakest Subject quizzes will tell you when this domain is no longer your biggest gap.

Start Preparing for the BCSP CHST Exam With Pocket Prep

Hazard and Risk Identification and Control is the largest domain on the exam, which means it’s also your biggest opportunity to pick up points. Pocket Prep’s BCSP CHST exam prep offers 400 practice questions across all four CHST5 domains, each with a detailed explanation of the reasoning behind the answer. Pair Build Your Own Quiz with Question of the Day to keep hazard controls fresh every day.

With a steady plan, you can walk into the test center ready for whatever the jobsite scenario throws at you.