CIH

The credential is administered by the Board for Global EHS Credentialing (BGC); legacy material sometimes names the American Board of Industrial Hygiene. This page is independent and unaffiliated - it is not reviewed, endorsed, or sponsored by BGC. Use BGC's website for eligibility requirements, applications, scheduling, and the authoritative content outline.

Those figures change between program years, so no number is given here. BGC publishes the current item count, appointment length, and passing standard in its candidate handbook. Check the handbook before you plan your pacing strategy rather than relying on numbers from older prep material or forum posts.

It is a computer-based, multiple-choice examination aligned to a published content outline covering exposure assessment, controls, risk assessment and management, community exposure, management and leadership, emergency response, and ethics. Expect applied items that require calculation, data interpretation, and judgment about the best professional course of action rather than simple definitions.

It is a rigorous, broad exam for experienced practitioners. Common failure modes are over-relying on memorized facts, neglecting quantitative items, and studying only one's daily specialty. Weak math and unit-conversion fluency, unfamiliarity with ventilation and statistics, and misreading questions that ask for the best or first action are frequent sources of lost points.

Retake rules, waiting periods, and any limits on attempts are set by BGC and change over time. Consult the current candidate handbook for the applicable policy before you register, and build in time for a re-application if needed. Do not assume an immediate retake is available.

Start with a diagnostic pass over every domain to find gaps, then front-load the highest-weight and most quantitative areas - exposure assessment and controls - because they anchor much of the rest. Layer in toxicology, epidemiology, and statistics, then finish with management, community exposure, emergency response, and ethics. Revisit weak domains repeatedly rather than once.

Substantial. Expect unit conversions, concentration and exposure calculations, sampling and analytical error, ventilation and dilution equations, noise averaging and dose, and basic statistics. Practice by hand without a formula sheet, and confirm what reference materials and calculator the test center permits, since that shapes how much you must memorize.

There is no official prerequisite study time. Most successful candidates report months of structured review built around the published outline. You are ready when you can score consistently above your target on full-length practice under real time constraints and can explain why each wrong answer is wrong, not just recognize the right one.

Eligibility depends on education, professional experience, and references, and the criteria are set solely by BGC. Requirements have changed over time, so verify against the current handbook rather than older study guides. Confirm eligibility before investing in preparation.

Recertification is required, typically through continuing education and professional activity over a defined cycle. The exact cycle, credit categories, and reporting deadlines are set by BGC and change periodically. Check the current recertification requirements on the BGC site and track credits as you earn them.