FREE CHST Study Guide 2026: All 4 Domains

This free CHST study guide walks through every content domain the Construction Health and Safety Technician exam tests, organized to the current Board of Certified Safety Professionals (BCSP) CHST examination blueprint.^[2]

It’s interactive, not a wall of text: every module has built-in checkpoint quizzes, flashcards, and practice questions, so you learn by doing — not just reading.

The CHST tests four official domains, all grounded in OSHA’s construction standards (OSHA 29 CFR 1926). We teach them in six study modules, splitting the heaviest domain — Hazard and Risk Identification and Control, about 37% of the exam — across the first two modules and leading with it.

Read a module, test yourself at each checkpoint, then drill gaps with our free practice test and flashcards. This guide is a high-yield overview that maps the official blueprint — not a full construction-safety textbook.

The CHST is construction-specific. If you’re studying the broader BCSP safety-science credential instead, see our ASP study guide; the two share fundamentals like the hierarchy of controls, but the CHST drills into OSHA 1926 construction operations.

CHST Exam Snapshot

The CHST covers four domains. The largest — Hazard and Risk Identification and Control — is more than a third of the exam (~37%), and the other three are close in weight. Study by weight, and ground everything in OSHA 29 CFR 1926:^[2]

Module 1 · Focus Four & Hazard Identification

Part of the largest domain — Hazard and Risk Identification and Control, ~37% of the exam. This module covers the conceptual core: how to tell a hazard from a risk, OSHA’s Focus Four (Fatal Four), and the hierarchy of controls you reach for to control them. Own this and you own the foundation of the CHST.

1.1 Hazards, Risk & the Focus Four

Start with the vocabulary. A Hazard is a condition or activity with the potential to cause harm; Risk combines how likely that harm is with how severe it would be. The first job of a CHST is hazard identification, and the most-tested framework is OSHA’s Focus Four (Fatal Four) — the four categories that cause most construction deaths.^[3]

The everyday tool for finding step-by-step hazards is the Job Hazard Analysis (JHA) — select the job, break it into steps, identify each step’s hazards, then assign controls (a JHA and a Job Safety Analysis are the same method by different names). Many CHST scenarios hinge on the Competent person: both elements — the ability to identify hazards and the authority to fix them — are required.

1.2 Falls & the Hierarchy of Controls

Falls are the single largest cause of construction deaths. Under 29 CFR 1926.501, fall protection is required for work 6 feet or more above a lower level — using a Guardrail system, a safety net, or a Personal fall arrest system (PFAS). Watch the trigger heights: scaffolds use 10 feet and steel erection generally 15 feet.^[4]

How you control any hazard — falls included — follows the hierarchy of controls, the single most useful framework on the exam.

1.3 Struck-By, Caught-In & Electrocution

The other three Focus Four hazards turn on precise definitions. A Struck-by hazard is impact from a forcible moving object — a vehicle, swinging load, or flying or falling object.

A Caught-in/between hazard involves being pinched, crushed, or buried; the distinguishing element is the compression or pinning (a worker pinned between a backing truck and a wall is caught-between, not struck-by). Electrocution comes from overhead power lines, missing GFCIs, and damaged cords.

Module 2 · Construction Operations & Controls

The rest of Hazard and Risk Identification and Control. This module drills the high-yield OSHA 1926 operations: excavation and trenching, scaffolds and confined spaces, and the chemical and energy programs — Hazard Communication, silica, and Lockout/Tagout. These are where the exam tests specific numbers, so know the triggers cold.

2.1 Excavation & Trenching

Trench cave-ins are a deadly caught-in hazard. Under 29 CFR 1926.652, a protective system is required whenever an Excavation is 5 feet or more deep, unless it is made entirely in stable rock. The choice of system depends on OSHA’s Soil classification.^[5]

A Competent person must classify the soil and may design sloping or benching for excavations up to 20 feet deep using OSHA’s appendices; systems deeper than 20 feet must be designed by a registered professional engineer. The protective methods are sloping, benching, shoring, and shielding (trench boxes).

2.2 Scaffolds, Ladders & Confined Spaces

On a Scaffold, fall protection is required above 10 feet (note the difference from the general 6-foot trigger), and scaffolds must be erected and dismantled only under a competent person’s supervision.^[6] Ladders need the right angle (about 4:1) and secure footing.

A Permit-required confined space (tank, vault, manhole) demands atmospheric testing before entry, in a specific order. The Atmospheric testing order is oxygen first, then combustible gases, then toxics — because most combustible-gas sensors need adequate oxygen to read accurately. The Acceptable oxygen range is 19.5 to 23.5 percent.

2.3 HazCom, Silica & Lockout/Tagout

The Hazard Communication Standard (HazCom) requires a written program, labels, training, and a Safety Data Sheet (SDS) — a standardized 16-section document — for every hazardous chemical. Labels follow the Globally Harmonized System (GHS): product identifier, signal word, hazard statements, pictograms, precautionary statements, and supplier information.^[8]

Respirable crystalline silica from cutting concrete and masonry causes silicosis and lung cancer; OSHA’s construction standard (1926.1153) sets a PEL of 50 µg/m³ and an action level of 25 µg/m³ (8-hour TWAs).^[7] Energy hazards during servicing are controlled with Lockout/Tagout (LOTO), and the order matters.

Module 3 · Emergency Prep & Incident Investigation

One official domain — Emergency Preparedness, Incident Investigation, and Response, ~20% of the exam. Two halves: planning and responding to emergencies before they happen, and investigating incidents (and near misses) to stop them from happening again.

3.1 Emergency Planning & Response

Every site needs an Emergency Action Plan (EAP) under OSHA 29 CFR 1910.38. It must cover emergency reporting, evacuation procedures and routes, accounting for all employees after evacuation, and rescue and medical duties. It must be written — though an employer with 10 or fewer employees may communicate it orally.^[9]

The element people forget is accounting for everyone: after evacuation, conduct a head count at the designated Assembly area against a current roster (including subcontractors and visitors). For a chemical spill, evacuate or isolate the area, alert trained responders, and consult the SDS — do not improvise cleanup.

3.2 Incident Investigation & Root Cause

When something does happen, follow a disciplined sequence rather than jumping to blame.

The goal is Root cause analysis (RCA) — finding the underlying system failures so corrective actions prevent recurrence. Two tools recur on the exam: the 5 Whys (keep asking “why” until you reach a root cause) and the Fishbone (Ishikawa) diagram (sort causes by people, equipment, methods, materials, environment).

Investigate not just injuries but near misses, which surface hazards before they cause loss. An investigation closes only when corrective actions are verified effective.

Module 4 · Incident Metrics & OSHA Recordkeeping

The measurement side of safety — spanning Emergency/Response and Program domains. The CHST expects you to calculate incident rates and to know OSHA’s recordkeeping rules cold. The math is simple once the formulas and the 200,000 base are automatic.

4.1 Incident Rates (TRIR, DART)

The rate everyone must know is the Total Recordable Incident Rate (TRIR): (recordable cases × 200,000) ÷ total hours worked. The 200,000-hour base represents 100 full-time workers at 2,000 hours each, so the result is “recordables per 100 workers.” The DART rate uses the same base but counts only days-away, restricted, or transferred cases.^[10]

4.2 OSHA Recordkeeping (300/301/300A)

Under OSHA’s recordkeeping rule (29 CFR Part 1904), employers with more than 10 employees (outside certain low-hazard exempt industries — construction is not exempt) must keep the records. An injury is an OSHA recordable if it involves death, days away, restricted work or transfer, medical treatment beyond first aid, loss of consciousness, or a significant diagnosis. The dividing line is medical treatment beyond first aid.

Module 5 · Safety Program Development & Sustainment

One official domain — Safety Program Development, Implementation, and Sustainment, ~22% of the exam. This is how a CHST builds, implements, measures, and sustains a safety management system over time — not just spots hazards on a given day.

5.1 Building the Program

OSHA’s Recommended Practices for Safety and Health Programs lay out seven core elements: management leadership, worker participation, hazard identification and assessment, hazard prevention and control, education and training, program evaluation and improvement, and communication/coordination. ^[11] Management leadership and worker participation are the foundation. When building from scratch, start by assessing existing conditions and current efforts.

The Job Hazard Analysis (JHA) feeds the program’s hazard-control work, and controls always follow the hierarchy of controls. On a Multi-employer worksite, communication and coordination among the general contractor and subcontractors are essential.

5.2 Leading & Lagging Indicators

A mature program tracks both kinds of metric. Lagging indicators (TRIR, DART, lost workdays) count outcomes after they happen; Leading indicators (inspections completed, near-misses reported, training completion, corrective-action close-out) are proactive and predictive. Leading indicators let you prevent the next injury rather than only count the last one.

5.3 Audits, Inspections & Sustainment

Know the difference: a Safety inspection finds physical hazards at a point in time; a Safety audit systematically evaluates whether the safety management system is in place and effective. A classic audit finding is a gap between the written program and what actually happens in the field. Likewise, Safety culture is the deep, enduring shared values about safety, while Safety climate is a snapshot of current perceptions (measured by a survey).

To sustain the program, embed safety responsibilities into defined roles, procedures, and routine reviews so the system persists regardless of personnel — and track corrective actions with an accountable owner, a due date, and verified closure.

Module 6 · Leadership, Communication & Training

One official domain — Leadership, Communication, and Training, ~21% of the exam. A CHST doesn’t just write rules; they change behavior through effective training, clear communication, and visible safety leadership.

6.1 Safety Training & Toolbox Talks

OSHA 29 CFR 1926.21 requires employers to instruct each employee in the recognition and avoidance of unsafe conditions and the regulations applicable to their work. The everyday vehicle is the Toolbox talk — a short (5–15 minute), job-specific meeting, best when its topic matches the day’s tasks and hazards (e.g., silica controls before saw-cutting). For a physical skill like donning a harness, hands-on demonstration and practice with a competency check beats lecture or video alone.

Document every session — topic, date, trainer, and attendees — so you can prove specific workers were trained on specific hazards. For a diverse workforce, use bilingual signage, standardized pictograms, and a qualified interpreter, and verify comprehension.

6.2 Safety Leadership & Communication

Safety leadership means visibly committing resources, setting expectations, and modeling safe behavior so the workforce follows. Leaders demonstrate it by allocating paid time, participating in briefings alongside crews, and responding to near-miss reports without blame — blame kills reporting. Effective communication is clear, concise, and relevant to the audience.

Adding Leading indicators (completed inspections, training completion, near-miss reports) gives leaders a proactive view of safety performance. Build lasting capacity by coaching frontline supervisors to lead briefings, conduct observations, and own hazard correction in their areas.

How to Use This CHST Study Guide

This guide is built to be worked, not just read. The most efficient path to a pass:

• Study by weight. Hazard and Risk Identification and Control is ~37% of the exam — start with Modules 1 and 2, then Program Development, Leadership/Training, and Emergency Response.
• Memorize the OSHA 1926 numbers. The 6-ft fall trigger, 10-ft scaffolds, 5-ft excavation, 19.5–23.5% oxygen, the 200,000 base, and silica 50/25 µg/m³ come up again and again.
• Check off as you go. Use the Study Guide Contents to mark each section done; it raises your exam-readiness score.
• Take every checkpoint. The end-of-module quizzes show you exactly which domains need another pass.
• Drill the weak domain. Send your weak area into the flashcards and a practice test until the score climbs.

CHST Glossary

The high-yield CHST terms in one place — hover any dotted term in the guide, or flip the whole deck here as a self-grading flashcard set.

200,000-hour base

The standardizing factor in OSHA rates — 100 full-time workers each working 2,000 hours per year.

5 Whys

An RCA technique that repeatedly asks 'why' to move past symptoms toward an underlying systemic cause.

Acceptable oxygen range

19.5 to 23.5 percent oxygen; below is oxygen-deficient, above is oxygen-enriched (raising fire risk).

Administrative controls

Controls that change how people work — permits, procedures, training, scheduling, rotation, signage. They depend on behavior, so they are weaker than engineering controls.

Angle of repose

The maximum slope at which a pile of loose material remains stable without sliding.

Assembly area

A designated muster point where workers gather after evacuation so they can be counted against a roster.

Atmospheric testing order

The sequence for testing a confined space before entry: oxygen first, then combustible gases, then toxic gases.

Caught-in/between hazard

An injury from being pinched, crushed, or compressed between objects, or buried (e.g., a trench cave-in or being pinned by equipment).

Competent person

Per 29 CFR 1926.32, someone able to identify existing and predictable hazards AND authorized to take prompt corrective measures to eliminate them.

Construction Health and Safety Technician (CHST)

A Board of Certified Safety Professionals (BCSP) credential for safety, health, and environmental practitioners in the construction industry, earned by passing the experience-based CHST exam.

DART rate

Days Away, Restricted, or Transferred rate: (DART cases × 200,000) ÷ total hours worked.

Electrocution

Death from electrical contact — overhead power lines, missing GFCIs, and damaged cords are leading construction causes.

Elimination

The most effective control — physically removing the hazard from the jobsite entirely.

Emergency Action Plan (EAP)

An OSHA 29 CFR 1910.38 plan covering emergency reporting, evacuation routes, accounting for employees, and rescue/medical duties (oral allowed for ≤10 employees).

Engineering controls

Controls that isolate people from a hazard by design — guardrails, ventilation, water suppression, machine guards, GFCIs — without relying on worker behavior.

Excavation

Any man-made cut, cavity, trench, or depression in an earth surface formed by earth removal.

Falls (Subpart M)

The leading cause of construction deaths; OSHA requires fall protection for work 6 feet or more above a lower level under 29 CFR 1926.501.

Fishbone (Ishikawa) diagram

A cause-and-effect diagram that organizes potential incident causes into categories (people, equipment, methods, materials, environment).

Focus Four (Fatal Four)

OSHA's four leading causes of construction worker deaths: falls, struck-by, caught-in/between, and electrocution.

Globally Harmonized System (GHS)

The international system, adopted by OSHA HazCom, that standardizes chemical classification and labeling (product identifier, signal word, hazard statements, pictograms, precautionary statements, supplier info).

Ground-fault circuit interrupter (GFCI)

A device that interrupts a circuit when it detects a ground fault, preventing electric shock; required for construction receptacles.

Guardrail system

A barrier (top rail ~42 inches, midrail, toeboard) erected along an exposed edge to prevent falls — a passive engineering control.

Hazard

A condition or activity with the potential to cause injury, illness, or damage.

Hazard Communication Standard (HazCom)

OSHA's standard (1910.1200, adopted for construction by 1926.59) requiring a written program, labels, safety data sheets, and training for hazardous chemicals.

Hierarchy of controls

Hazard controls ranked most to least effective: elimination, substitution, engineering controls, administrative controls, then personal protective equipment.

Hot work permit

An authorization that controls tasks producing heat or sparks (welding, cutting, grinding) near flammable materials.

Job Hazard Analysis (JHA)

A technique that breaks a job into steps, identifies the hazard of each step, and assigns controls; also called a Job Safety Analysis (JSA).

Lagging indicators

Reactive safety metrics measured after incidents — TRIR, DART, lost workdays, fatalities.

Leading indicators

Proactive, predictive safety metrics measured before incidents — inspections completed, near-misses reported, training delivered, corrective actions closed.

Lockout/Tagout (LOTO)

The procedure that isolates and de-energizes hazardous energy, locks and tags the device, and verifies a zero-energy state before servicing.

Multi-employer worksite

A construction site with a general contractor and subcontractors, where communication and coordination of safety are essential.

Near miss

An unplanned event that had the potential to cause injury or damage but did not — a leading indicator of latent hazards.

OSHA 29 CFR 1926

OSHA's Safety and Health Regulations for Construction — the body of standards that governs construction worksites and the basis for most CHST exam content.

OSHA 300 Log

The Log of Work-Related Injuries and Illnesses — one line per recordable case during the year.

OSHA 300A

The annual summary of recordable cases, posted from February 1 through April 30 and certified by a company executive.

OSHA 301

The Injury and Illness Incident Report that captures the detail behind each 300 Log entry.

OSHA recordable

A work-related case involving death, days away, restricted work or transfer, medical treatment beyond first aid, loss of consciousness, or a significant diagnosis.

Permit-required confined space

A confined space with a hazardous atmosphere, engulfment risk, entrapment configuration, or other serious hazard, requiring a permit and atmospheric testing before entry.

Personal fall arrest system (PFAS)

A system to stop a fall: a full-body harness, a connecting device (lanyard or self-retracting lifeline), and an anchorage.

Personal protective equipment (PPE)

The last line of defense (hard hats, harnesses, respirators, hearing protection). It does not remove the hazard and sits at the bottom of the hierarchy.

Protective system (excavation)

A method of protecting workers from cave-ins — sloping, benching, shoring, or shielding (trench box) — required at 5 feet deep or more unless in stable rock.

Qualified person

Someone who, by recognized degree, certificate, or extensive knowledge, training, and experience, has demonstrated the ability to solve problems relating to the work.

Respirable crystalline silica

Fine silica dust from cutting concrete, masonry, or stone; OSHA's construction PEL is 50 µg/m³ and the action level 25 µg/m³ (1926.1153).

Risk

The combination of the likelihood that a hazard causes harm and the severity of that harm.

Root cause analysis (RCA)

A structured investigation into the underlying system causes of an incident, so corrective actions prevent recurrence.

Safety audit

A systematic evaluation of whether the safety management system itself is in place, documented, and effective.

Safety climate

A snapshot of workers' current perceptions of safety, often measured by a perception survey.

Safety culture

The deep, enduring shared values and beliefs about safety in an organization — how people act when no one is watching.

Safety Data Sheet (SDS)

A standardized 16-section GHS document giving the hazards, handling, exposure controls, and emergency measures for a chemical.

Safety inspection

A point-in-time walk-through that identifies physical hazards and unsafe conditions on the jobsite.

Scaffold

A temporary elevated platform for workers and materials; fall protection is required above 10 feet under 29 CFR 1926.451.

Soil classification

OSHA's ranking of excavation soil from most to least stable: Stable Rock, Type A, Type B, Type C, used to select the protective system.

Struck-by hazard

An injury from a forcible moving object striking a worker — a vehicle, swinging load, or flying or falling object.

Substitution

Replacing a hazard with a less hazardous alternative (e.g., a wet-cut saw for dry cutting); second only to elimination.

Toolbox talk

A short (5–15 minute), informal, job-specific safety meeting, often held before a shift.

Total Recordable Incident Rate (TRIR)

(Recordable cases × 200,000) ÷ total hours worked — recordable injuries and illnesses per 100 full-time workers.

Trench

A narrow excavation (deeper than it is wide, generally ≤15 feet wide at the bottom).

Type A soil

Cohesive soil with unconfined compressive strength of at least 1.5 tons per square foot (e.g., clay, hardpan) — the most stable soil class.

Type C soil

The least stable soil class — granular, submerged, or with freely seeping water; requires the flattest sloping.

CHST Study Guide FAQ

References

1. 1.Board of Certified Safety Professionals. “Construction Health and Safety Technician (CHST).” bcsp.org. ↑
2. 2.Board of Certified Safety Professionals. “CHST Examination Blueprint.” bcsp.org. ↑
3. 3.Occupational Safety and Health Administration. “Construction Focus Four Hazards.” osha.gov. ↑
4. 4.Occupational Safety and Health Administration. “Duty to Have Fall Protection — 1926.501.” osha.gov. ↑
5. 5.Occupational Safety and Health Administration. “Excavations — Requirements for Protective Systems — 1926.652.” osha.gov. ↑
6. 6.Occupational Safety and Health Administration. “Scaffolds — General Requirements — 1926.451.” osha.gov. ↑
7. 7.Occupational Safety and Health Administration. “Respirable Crystalline Silica — 1926.1153.” osha.gov. ↑
8. 8.Occupational Safety and Health Administration. “Hazard Communication — 1910.1200.” osha.gov. ↑
9. 9.Occupational Safety and Health Administration. “Emergency Action Plans — 1910.38.” osha.gov. ↑
10. 10.Occupational Safety and Health Administration. “Injury and Illness Recordkeeping (29 CFR 1904).” osha.gov. ↑
11. 11.Occupational Safety and Health Administration. “Recommended Practices for Safety and Health Programs.” osha.gov. ↑
12. 12.National Institute for Occupational Safety and Health (CDC). “Hierarchy of Controls.” cdc.gov/niosh. ↑
13. 101.Occupational Safety and Health Administration (OSHA). “Job Hazard Analysis (OSHA 3071).” osha.gov, accessed 20 June 2026. ↑
14. 102.Occupational Safety and Health Administration (OSHA). “Excavations — Definitions (Soil Classification) — 1926.650.” osha.gov, accessed 20 June 2026. ↑
15. 103.Occupational Safety and Health Administration (OSHA). “Definitions — Competent Person — 1926.32.” osha.gov, accessed 20 June 2026. ↑
16. 104.Occupational Safety and Health Administration (OSHA). “Confined Spaces in Construction — 1926 Subpart AA.” osha.gov, accessed 20 June 2026. ↑
17. 105.Occupational Safety and Health Administration (OSHA). “Incident Investigation — Recommended Practices.” osha.gov, accessed 20 June 2026. ↑
18. 106.Occupational Safety and Health Administration (OSHA). “Safety and Health Training — 1926.21.” osha.gov, accessed 20 June 2026. ↑

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