Certified Industrial Hygienist (CIH): Requirements, Exam and Maintenance

The CIH is issued by the Board for Global EHS Credentialing (BGC). The board was founded in 1960 as the American Board of Industrial Hygiene (ABIH) and publicly announced its current name in 2019, after it grew beyond the CIH to offer other credentials. Many job postings and older resumes still say ABIH, and both names refer to the same issuer.

BGC describes a CIH as someone who anticipates, recognizes, evaluates and controls chemical, physical, ergonomic and biological hazards. In practice that means planning and running exposure assessments, interpreting sampling data, recommending controls and managing the programs that keep them working. If your work is mostly safety programs, incident investigation or compliance paperwork, the CIH may not match what you do every day, and a safety credential could fit better.

BGC's eligibility rules start with your degree. As of this writing, you need a bachelor's degree in biology, chemistry, physics or engineering, or a degree from an ABET-accredited industrial hygiene or safety program. A bachelor's degree in another field can qualify if it includes at least 60 semester hours of science, math, engineering or science-based technology, with at least 15 of those hours at the upper level. Social science courses do not count, and neither do credit-by-exam programs such as CLEP. If your degree falls short, BGC accepts added academic science coursework or a related graduate degree as a fix.

On top of the degree, you need industrial hygiene coursework: 180 academic contact hours or 240 continuing education contact hours. At least half must cover toxicology, fundamentals and measurements or controls. BGC counts one semester hour as 15 academic hours or 20 continuing education hours. You also need at least 2 contact hours of ethics training, which does not count toward the industrial hygiene total.

A practical tip: collect your course certificates as you go. BGC asks for proof of contact hours, and an agenda is needed when a certificate does not state them. Rebuilding that record years later is where many applicants lose time.

You need at least 48 months of professional-level industrial hygiene experience, and you must be practicing industrial hygiene when you apply. BGC judges professional level by four tests: how independently you work, the depth of your data gathering and interpretation, how widely you interact with decision-makers, and whether you are responsible for outcomes.

Breadth matters as much as length. Your experience must cover the full process from anticipation to control and management, across at least two of the four stressor categories: chemical, physical, biological and ergonomic. Narrow work, such as only asbestos, lead or mold, or only one stressor, counts for at most one year. A completed ABET-accredited industrial hygiene degree can stand in for part of the experience: 6 months for a bachelor's degree, and one year for a master's or a conferred doctorate, with one year as the overall cap.

References are the step that most often surprises applicants. BGC requires at least two Professional Reference Questionnaires. One must come from a colleague or supervisor who can speak to your current practice and your whole claimed period, and one must come from a CIH who knows your work. If you have no CIH reference, BGC accepts a reference from a professional-level holder of a credential recognized through the International Occupational Hygiene Association, or, failing that, three written work samples that you authored. You contact your own references, and each one submits directly to BGC. Wording copied across references can trigger an investigation, so brief each person separately.

You apply online through BGC's candidate portal, have each university send official transcripts directly to BGC, document your coursework and describe your experience in specific terms. Materials must be postmarked by February 1 for the spring exam or August 1 for the fall exam. Testing runs April 1 to May 31 in spring and October 1 to November 30 in fall, at Pearson VUE.

BGC lists the exam as 180 multiple-choice questions, 150 plus 30 pilot questions, in two sections of 2.5 hours each with an optional 30-minute break between them. Questions are mixed across subject areas rather than grouped. Every question carries the same weight, there is no penalty for a wrong answer, and passing depends on your total correct answers, not on a minimum in each area. If you do not pass, you can retest in the next window.

BGC publishes 16 subject areas for the exam:

BGC's current fee listing shows a $160 application fee and a $370 exam scheduling fee. The application fee covers a two-year eligibility window, which is four exam windows. If you cancel at least 48 hours before your appointment, the exam fee carries over to a later date within that window. If you do not pass in two years, you reapply with updated references and pay the application fee again.

After you pass, BGC charges an annual maintenance fee, listed at $180 for a full year. Unpaid annual fees for two years in a row lead to decertification. Fees are only part of the cost: prep courses, reference books and time off for study usually cost more, and many employers reimburse some of it. Ask before you pay.

CIH holders recertify every five years. The standard route is certification maintenance points: 40 points over the 60-month cycle, including at least 10 points (60 hours) from educational programs and 2 hours of ethics. Points can also come from active practice, committee or board service, publishing, and teaching or presenting. Extra points do not roll into the next cycle. BGC posts each holder's due date in the candidate portal and sends reminders in the last six months of the cycle.

You can also recertify by retaking the CIH exam within the 18 months before your certification expires, with the same ethics requirement. Most working hygienists find points easier, because conferences, courses and day-to-day practice already generate them. Log activities as they happen rather than at the end of the cycle.

When a posting lists the CIH as required, the employer usually needs someone who can sign off on exposure assessments, defend sampling strategies to regulators or clients, or lead an industrial hygiene program across sites. Consulting firms often need it because clients ask for it by name. When the CIH is listed as preferred, documented sampling experience and a clear plan toward eligibility can still earn an interview.

If you are working toward the CIH, say so on your resume with specifics: the stressor categories you have assessed, the instruments and methods you have used, and your expected eligibility date. Hiring managers look for evidence that you have planned and run assessments yourself, not just helped. Before you apply, read BGC's current candidate handbook. The issuer's own requirements are the only ones that count.