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Exam Review

Key Facts: HAZWOPER 24 Exam

24 hrs + 1 day

Initial Training Requirement

29 CFR 1910.120(e)(3)(ii)

8 hours

Annual Refresher

29 CFR 1910.120(e)(8)

16 hrs + 2 days

Upgrade to 40-Hour Tier

29 CFR 1910.120(e)(3)(iv)

19.5%

Oxygen-Deficiency Threshold

29 CFR 1910.134

>25% LEL

Withdraw — Explosion Hazard

NIOSH/OSHA/USCG/EPA Guidance Manual

30 days/year

Medical Surveillance Trigger

29 CFR 1910.120(f)(2)

~70%

Typical Provider Pass Mark

Online HAZWOPER training providers

The HAZWOPER 24-hour course serves occasional hazardous waste site workers — surveyors, groundwater samplers, geophysical technicians, inspectors — covered by 29 CFR 1910.120(e)(3)(ii), plus regular workers on fully characterized below-PEL sites under (e)(3)(iii). OSHA requires 24 hours of instruction plus one day of supervised field experience; workers who later become general site workers or need respirators must add 16 hours and two field days to reach the 40-hour tier. Provider exams test seven core areas: training and medical-surveillance regulations; toxicology (routes of entry, PEL/TLV/IDLH, asphyxiants); site control (exclusion/contamination-reduction/support zones, buddy system, HASP); PPE Levels A-D and respirator rules (APRs prohibited in IDLH or below 19.5% oxygen); air monitoring (oxygen first, withdraw above 25% LEL, PID cannot read methane); decontamination line sequence; and emergency response plans. Most online courses charge $150-$250 and require about 70% on a multiple-choice final, with module quizzes along the way. An 8-hour refresher each year under (e)(8) keeps the certification current.

Sample HAZWOPER 24 Practice Questions

Try these sample questions to review concepts for the HAZWOPER 24 exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which provision of OSHA's HAZWOPER standard sets the 24-hour initial training requirement for workers who are on site only occasionally for a specific limited task?

A.29 CFR 1910.120(e)(3)(ii)

B.29 CFR 1910.120(e)(3)(i)

C.29 CFR 1910.120(q)(6)(iii)

D.29 CFR 1910.120(e)(8)

Explanation: 29 CFR 1910.120(e)(3)(ii) covers workers on site only occasionally for a specific limited task (such as groundwater monitoring, land surveying, or geophysical surveying) who are unlikely to be exposed over permissible exposure limits; they must receive a minimum of 24 hours of off-site instruction plus one day of supervised field experience.

2In addition to 24 hours of instruction off the site, what field experience does 1910.120(e)(3)(ii) require for occasional site workers?

A.Three days of field experience under a trained, experienced supervisor

B.Two days of unsupervised on-site orientation

C.One day of actual field experience under the direct supervision of a trained, experienced supervisor

D.A 4-hour site-specific video briefing

Explanation: 1910.120(e)(3)(ii) requires a minimum of 24 hours of instruction off the site AND a minimum of one day of actual field experience under the direct supervision of a trained, experienced supervisor.

3Which worker is an appropriate candidate for the 24-hour occasional site worker training tier rather than the 40-hour tier?

A.A laborer who excavates contaminated soil inside the exclusion zone every day

B.A land surveyor who occasionally performs boundary surveys on site and is unlikely to be exposed above any PEL

C.An employee required to wear an air-purifying respirator during weekly sampling

D.A member of the site emergency response HAZMAT team

Explanation: 1910.120(e)(3)(ii) specifically lists tasks like land surveying, groundwater monitoring, and geophysical surveying performed occasionally by workers unlikely to be exposed over PELs and published exposure limits as qualifying for the 24-hour tier.

4A 24-hour trained occasional worker is reassigned as a general site worker who must wear a respirator. What additional training does 1910.120(e)(3)(iv) require?

A.Only the 8-hour annual refresher

B.A new 24-hour course taken from the beginning

C.Eight additional hours of supervisor training

D.Sixteen additional hours of instruction and two additional days of supervised field experience

Explanation: Under (e)(3)(iv), workers trained at the 24-hour level who become general site workers or who are required to wear respirators must receive 16 more hours of instruction and two more days of field experience, bringing their total to the full 40 hours and three days required by (e)(3)(i).

5How much refresher training must HAZWOPER-trained site workers receive to keep their training current?

A.Four hours every two years

B.Twenty-four hours every three years

C.Eight hours of refresher training annually

D.Forty hours every five years

Explanation: 1910.120(e)(8) requires employees and supervisors to receive eight hours of refresher training annually on the items in the initial training curriculum and other relevant topics such as incident critiques.

6What additional training does 1910.120(e)(4) require for on-site managers and supervisors directly responsible for employees engaged in hazardous waste operations?

A.At least 8 additional hours of specialized training on managing hazardous waste operations

B.No additional training beyond the worker tier they supervise

C.An additional 16 hours plus two days of field experience

D.A college degree in occupational safety and health

Explanation: Under (e)(4), supervisors must receive the same training as the employees they supervise plus at least eight additional hours of specialized training on topics such as the safety and health program, PPE program, spill containment, and health hazard monitoring.

7Workers who are REGULARLY on site (not just occasionally) may also qualify for 24-hour training under 1910.120(e)(3)(iii) only if which condition is met?

A.They work fewer than 30 days per year on the site

B.Their supervisor holds a 40-hour certificate and approves the reduction in writing

C.They are enrolled in a medical surveillance program

D.The site has been fully characterized, exposures are below PELs and published exposure limits, respirators are not necessary, and no health hazards or emergency-causing conditions exist

Explanation: Paragraph (e)(3)(iii) allows 24 hours plus one day of field experience for regular workers only where the site is fully characterized and monitored, exposures are under PELs and other published exposure limits, respirators are not needed, and the characterization shows no health hazards or possible emergencies.

8Which OSHA standard applies the identical HAZWOPER requirements to hazardous waste operations performed in the construction industry?

A.29 CFR 1903.2

B.29 CFR 1926.65

C.29 CFR 1904.39

D.49 CFR 172.704

Explanation: 29 CFR 1926.65 is the construction-industry counterpart of 1910.120 and contains identical HAZWOPER requirements, including the (e)(3) training tiers.

9Under 1910.120(f), which employees must be included in the employer's medical surveillance program?

A.Employees exposed to hazardous substances at or above the PELs or published exposure levels for 30 days or more a year

B.All employees who ever set foot on a hazardous waste site, regardless of exposure

C.Only employees who request a medical examination in writing

D.Only employees older than 40 years of age

Explanation: Medical surveillance is required for employees exposed at or above PELs or published exposure levels for 30 or more days a year, employees who wear respirators 30 or more days a year, HAZMAT team members, and employees injured or showing signs of overexposure.

10How often must covered employees receive medical examinations under the HAZWOPER medical surveillance program?

A.Every 6 months without exception

B.Only after an exposure incident occurs

C.At least once every 12 months, unless the physician believes a longer interval (not greater than every two years) is appropriate

D.Every five years after the baseline examination

Explanation: 1910.120(f)(3) requires examinations prior to assignment, at least once every twelve months thereafter unless the attending physician believes a longer interval (not exceeding biennially) is appropriate, at termination or reassignment, and as soon as possible after signs of overexposure.

About the HAZWOPER 24 Exam

HAZWOPER 24-Hour Initial Training is the OSHA-required tier under 29 CFR 1910.120(e)(3)(ii) for workers who visit hazardous waste sites only occasionally for specific limited tasks — such as groundwater monitoring, land surveying, or geophysical surveying — and who are unlikely to be exposed over PELs or published exposure limits. It also covers workers regularly on fully characterized sites where exposures stay below limits and respirators are unnecessary under (e)(3)(iii). The requirement is 24 hours of off-site instruction plus one day of actual field experience under a trained, experienced supervisor, with written certification before site work. Course final exams are provider-administered, usually multiple-choice with a 70% pass mark, and certification stays current through the 8-hour annual refresher required by 1910.120(e)(8).

Exam sponsor: OSHA-compliant training providers under 29 CFR 1910.120(e) / 1926.65(e). The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

Question count not published by the exam provider

Time Limit

24 hours of instruction; provider final exams are typically untimed or limited to 1-2 hours

Passing Score

Typically 70% on the provider's final exam, with module quizzes throughout the course

Exam / Certification Fees

$150-$250 typical for online 24-hour courses (set by the training provider)

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Official sources

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

14%

OSHA Regulations & Training Requirements

29 CFR 1910.120(e)(3)(ii) occasional-worker tier (24 hours + 1 day field experience), (e)(3)(iii) characterized sites, (e)(3)(iv) 16-hour upgrade to 40-hour, (e)(4) supervisor training, (e)(8) 8-hour annual refresher, written certification, and 1910.120(f) medical surveillance triggers

16%

Toxicology & Hazard Recognition

Routes of entry (inhalation primary), PELs vs TLVs vs RELs, STELs and ceilings, IDLH, action levels, acute vs chronic effects, LD50/LC50, simple vs chemical asphyxiants, H2S olfactory fatigue, flash point, LEL/UEL, vapor density, NFPA 704, and SDS sections

15%

Site Characterization & Control

Exclusion/contamination reduction/support zones, hotline and contamination control line, buddy system, site control program elements, preliminary evaluation, presumed-IDLH conditions, HASP contents under (b)(4), pre-entry briefings, drum handling, bonding/grounding, and heat stress

16%

Personal Protective Equipment

PPE Levels A-D selection criteria, Level B minimum for initial entry, APR restrictions (not IDLH, oxygen at least 19.5%, known contaminants), SCBA requirements, permeation vs penetration vs degradation, breakthrough time, seal checks, annual fit testing, and (g)(5) PPE program elements

13%

Air Monitoring & Instrumentation

Monitoring sequence (oxygen first, then LEL, then toxics), oxygen deficiency below 19.5% and enrichment above 23.5%, percent-LEL action levels (withdraw above 25% LEL), PID lamp limitations (no methane at 10.6 eV), FID, detector tube accuracy, 4-gas meters, and bump testing

12%

Decontamination

Decon procedures before entry under (k)(2), contamination reduction corridor layout from dirty to clean, respirator removed near the end, decon-worker protection, managing rinse water as hazardous waste, swipe testing effectiveness, wetted permeable clothing, and emergency decon

14%

Emergency Response & Medical Surveillance

Written emergency response plan before operations under (l), required plan elements, evacuation vs response (1910.38 option), awareness vs operations responder actions, rescue hazards, heat stroke vs heat exhaustion, physician's written opinion, and 30-year record retention under 1910.1020

Preparing for the HAZWOPER 24 Exam

What You Need to Know

Passing score: Typically 70% on the provider's final exam, with module quizzes throughout the course
Assessment: Question count not published by the exam provider
Time limit: 24 hours of instruction; provider final exams are typically untimed or limited to 1-2 hours
Exam / certification fees: $150-$250 typical for online 24-hour courses (set by the training provider) Official sources

Using Our Practice Resources

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HAZWOPER 24: Suggested Study Strategy

1Memorize the training matrix cold: 40 hours + 3 days for general site workers under (e)(3)(i); 24 hours + 1 day for occasional and characterized-site workers under (e)(3)(ii)/(iii); 16 hours + 2 days to upgrade under (e)(3)(iv); 8-hour annual refresher under (e)(8).

2Learn the PPE levels by what changes: A and B both use SCBA (identical respiratory protection) but only A is vapor-tight encapsulating; C swaps in an air-purifying respirator (never in IDLH, never below 19.5% oxygen, contaminants must be known); D is just a work uniform.

3Drill the air monitoring numbers: oxygen first (19.5% deficient, 23.5% enriched), withdraw above 25% LEL, PID with a 10.6 eV lamp cannot detect methane (IP 12.61 eV), detector tubes are only accurate to about plus-or-minus 25%.

4Picture the three zones when answering site-control questions: exclusion zone (hot) inside the hotline, contamination reduction zone with the decon corridor, support zone (clean) upwind — and remember the respirator comes off near the END of the decon line.

5Know the medical surveillance triggers: 30+ days/year exposed at or above PELs, 30+ days/year wearing a respirator, HAZMAT team membership (no day threshold), and symptom reports — exams annually unless the physician extends to every two years.

6Distinguish heat stroke (hot, dry skin, confusion — call EMS and cool aggressively) from heat exhaustion (cool, clammy, sweating — rest, fluids, shade); impermeable suits cause heat illness by blocking sweat evaporation.

Frequently Asked Questions

Who needs HAZWOPER 24-hour training instead of the 40-hour course?

Under 29 CFR 1910.120(e)(3)(ii), workers who are on a hazardous waste site only occasionally for a specific limited task — OSHA's examples are groundwater monitoring, land surveying, and geophysical surveying — and who are unlikely to be exposed over PELs and published exposure limits qualify for 24 hours plus one day of field experience. Workers regularly on fully characterized, below-PEL sites where respirators are unnecessary also qualify under (e)(3)(iii). General site workers exposed to hazardous substances need the 40-hour course under (e)(3)(i).

How much field experience does the 24-hour tier require?

One day of actual field experience under the direct supervision of a trained, experienced supervisor, in addition to the 24 hours of off-site instruction. The 40-hour tier requires three days. The field experience comes from your employer at an actual site — online providers cannot supply it.

What happens if my duties change after taking the 24-hour course?

If you become a general site worker or your tasks require a respirator, 1910.120(e)(3)(iv) requires 16 additional hours of instruction and two additional days of supervised field experience to bring you to the full 40-hour/3-day level. Your original 24 hours are credited — you do not repeat the whole course.

Does HAZWOPER 24 certification expire?

The certification stays current only with an 8-hour refresher every year under 1910.120(e)(8). If the refresher lapses, OSHA interpretation guidance says to take it as soon as possible, and the employer must evaluate whether the length of the lapse and the worker's familiarity with procedures warrant repeating initial training.

What is on the HAZWOPER 24 final exam?

Provider exams cover the (e)(3)(ii) training framework, toxicology and exposure limits (PEL, TLV, IDLH, routes of entry), site work zones and the buddy system, PPE Levels A-D and respirator selection rules, air monitoring instruments (oxygen first, percent-LEL action levels, PID/FID limitations), decontamination line sequence, and emergency response plan elements. Most providers require about 70% to pass, with quizzes after each module.

How much does the 24-hour course cost and how long does it take?

Online 24-hour courses typically run $150-$250. The coursework itself is 24 hours of instruction, and most students spread it over one to two weeks of self-paced study before taking the final exam.

Can a 24-hour trained worker enter an IDLH atmosphere?

No. The 24-hour tier exists precisely because the worker is unlikely to be exposed over PELs. IDLH conditions require positive-pressure SCBA or supplied air with escape bottle under 1910.120(g)(3)(iv), and respirator-wearing workers must be trained to the 40-hour level under (e)(3)(iv).