The Certified Industrial Hygienist credential, awarded by the American Board of Industrial Hygiene, is one of the most respected certifications in occupational health and safety. Earning the CIH demonstrates that you have the education, experience, and technical knowledge to anticipate, recognize, evaluate, and control workplace health hazards. The examination is demanding — 200 multiple-choice questions across four hours — and the content spans chemical exposure assessment, physical stressors, biological hazards, ergonomics, and industrial hygiene program management.
This free CIH practice test PDF gives you a printable set of questions and explanations you can study anywhere. Use it during your commute, over lunch, or in any setting where pulling up an online practice platform is inconvenient. Print it, annotate it, and return to the questions you missed until the underlying concepts are solid. Pair the PDF with structured study across each content domain for the most effective exam preparation.
Chemical stressors represent the largest single content domain on the CIH examination. You will be expected to understand the routes of exposure (inhalation, skin absorption, ingestion, and injection), the toxicological mechanisms by which chemicals cause harm, and the quantitative methods used to assess and characterize worker exposure.
Air sampling strategy is a central topic: when to use personal versus area sampling, how to select the correct collection media, how to calculate time-weighted average (TWA) exposures, ceiling values, and short-term exposure limits (STELs). The exam tests your ability to interpret industrial hygiene survey data and determine whether measured exposures comply with occupational exposure limits published by OSHA (PELs), NIOSH (RELs), and ACGIH (TLVs). You should be comfortable reading air monitoring reports, identifying sampling errors, and recommending corrective actions when exceedances are found.
Understanding the differences between PELs, RELs, and TLVs is essential. OSHA PELs are legally enforceable but were largely set in the early 1970s and are widely considered outdated for many substances. NIOSH RELs and ACGIH TLVs are updated more frequently based on current toxicological data and are generally more protective. Industrial hygienists are expected to understand when to recommend limits more stringent than the OSHA PEL, particularly for carcinogens or substances with new epidemiological evidence of harm.
Physical stressors covered on the CIH exam include noise, heat and cold stress, non-ionizing radiation (ultraviolet, infrared, radiofrequency, microwave, and laser), vibration, and ergonomic risk factors. Each stressor has its own exposure metrics, threshold values, and control approaches.
For noise, you need to understand sound level measurements in decibels, the exchange rate (5 dB per OSHA standards, 3 dB under NIOSH/ACGIH), permissible noise exposure tables, and the hierarchy of noise controls — engineering controls (enclosures, vibration isolation, material substitution) before administrative controls (job rotation, reduced exposure time) and hearing protection as a last resort. For heat stress, understand the wet bulb globe temperature (WBGT) index, heat illness progression from heat cramps through heat exhaustion to heat stroke, and the physiological basis of acclimatization.
Ergonomics questions may address musculoskeletal disorder risk factors — force, repetition, awkward postures, contact stress, and vibration — as well as evaluation tools such as NIOSH Lifting Equation calculations, RULA, REBA, and OSHA ergonomics guidelines. The exam may ask you to calculate recommended weight limits or identify which job elements pose the greatest ergonomic risk.
Biological hazards in occupational settings include bacteria, viruses, fungi, and parasites. Industrial hygienists working in healthcare, agriculture, wastewater treatment, and food processing must understand routes of exposure, biosafety levels, appropriate personal protective equipment, and engineering controls such as biosafety cabinets and HEPA filtration. Bloodborne pathogen standards and respiratory protection for airborne infectious agents are commonly tested.
Ionizing radiation topics include the types of radiation (alpha, beta, gamma, X-ray, neutron), penetrating ability, units of measurement (rad, rem, gray, sievert), dose limits for occupational and general public exposures, and the ALARA (As Low As Reasonably Achievable) principle. You should understand the inverse square law as it applies to point source radiation intensity and the use of time, distance, and shielding as primary controls. Radiological survey instruments — Geiger-Mueller counters, ionization chambers, scintillation detectors — and their appropriate applications are also testable content.
The management domain tests your ability to operate an IH program within an organization, communicate risk findings to stakeholders, write and implement written programs, and understand the regulatory framework governing occupational health. This includes knowledge of key OSHA standards (29 CFR 1910 for general industry, 29 CFR 1926 for construction), the OSHA inspection and citation process, and workers' rights under Section 11(c) of the OSH Act.
Cost-benefit analysis of controls, budget justification for safety investments, and communication of complex technical findings to non-technical audiences are recurring themes. The exam may present scenarios where you must prioritize among multiple hazards given limited resources, recommend feasible engineering controls rather than defaulting to PPE, or evaluate whether a proposed control adequately reduces exposure below the applicable limit. Familiarity with how industrial hygiene integrates with broader environmental health and safety (EHS) management systems — including ISO 45001 and ANSI Z10 — rounds out this domain.
Thorough preparation across all six content domains — not just the areas you encounter most in your daily work — is what separates candidates who pass on their first attempt from those who need to retake. The CIH exam rewards both breadth of knowledge and the ability to apply concepts to realistic workplace scenarios. Use this PDF to benchmark your readiness, then target your remaining study time on the domains where the practice questions revealed gaps. For additional full-length timed practice sets with detailed explanations, visit the cih practice test page.