Confessions of a Certified Industrial Hygienist (CIH) Examinee interviews recent successful examinees of the Certified Industrial Hygienist (CIH) exam administered by the American Board of Industrial Hygiene (ABIH).  The resultant text is as follows:  When did you decide to take the CIH exam?

Examinee:  I decided in 2003 to make it a goal of mine to obtain the CIH certification.  When did you obtain certification?

Examinee:  I actually obtained certification in May 2010.  What is your current career field and how do you feel it prepared you?

Examinee:  Currently I am in the consulting field.  I feel that it (i.e. being a consultant) prepared me by having the ability to complete a multitude of traditional IH projects.  The great thing about being a consultant is that there is always something new and fresh in meeting the needs of the client, which exposes you to a variety of the traditional “IH rubrics”.  How long had you been in the IH/Safety career field when you sat for the CIH exam?

Examinee:  Less than 10 years.  I believe it was actually 9 years.  While you can take the test after 5 years, I have always personally regarded the CIH designation highly.  I felt that it was important and wanted to have a certain “skillset” prior to sitting for the exam.  Are you saying that you did not just want to have a “certification” but wanted to be able to exemplify the characteristics of most CIH’s in the field?

Examinee:  Exactly.  That is precisely my thoughts and feelings.  What was/is your work/career-life like?

Examinee:  I consider myself very fortunate to have a very well qualified mentor (who is a CIH) and excellent IH support staff around me.  Personally, I feel that it would have been much more difficult to obtain such a high level IH skillset without those continuing resources.  Personally, how many hours do you think you studied in preparation for the CIH exam?

Examinee:  Great question.  But one that I thought about many times after many months of studying.  I’d imagine that I studied somewhere in the range of 700-800 hours in all.  Granted, this was over a few years.  However, over the final year leading up to the exam, the final breakdown was probably somewhere in the range of:

  • > 12 months out = 120 hours
  • 12 – 6 months out = 200 hours
  • 6  – 3 months out = 200 hours
  • 3 – 1 months out = 120 hours
  • < 1 month out = 60-90 hours  How would you breakdown your study time?

Examinee:  By…

Reading & Studying:

  • White Book
  • NSC Fundamentals Book
  • AIHA IH Reference & Study Guide


  • UNC Comprehensive IH Review
  • Burton Elemental Industrial Hygiene Review

Practicing:  What did you think of’s CIH Exam Prep Questions?

Examinee:  Is this a loaded question?  Actually, the questions in’s resources very closely represented the questions presented in the CIH exam.  How about DataChem’s software?

Examinee:  Being a statistical “nerd”, I actually kept stats on the accuracy of the questions I got correct while practicing with DataChem.  While using the software, over the course of approximately 2000 questions, I achieved approximately 71%.  While this number may not translate exactly to the CIH exam, I can tell you that I did score higher, as an average, over the rubrics on the CIH exam.  And, I passed the CIH exam on the first attempt.  Therefore, I tell you this because I feel that if you can study intensely, then prior to taking the CIH exam work DataChem and score > 70%, I’d feel comfortable in telling you that you should pass the exam.  Hasn’t DataChem been acquired by another company?

Examinee:  Yes, I believe it has been acquired by another laboratory group.  However, if you have considered the CIH exam in the last 15+ years, you have heard about “DataChem” and their software.  What can you tell us about the exam?

Examinee:  It is 250 questions, broken up into 2 parts (125 questions each part) of 3.5 hours each (i.e. 7 hours for the full exam).  When you end the first section, you have exactly one hour to get back into the exam room to start section 2 or else your time starts automatically.  So, prepare for lunch (e.g. have somewhere close-by to pick up lunch, bring a packed lunch, etc.).

You are now given pencil and paper, instead of the whiteboards that were given a few years back.  Much more conducive to IH’s who want to work out problems and reference equations/examples later on.  Believe me, you will repeat formulas, question-types, etc. throughout the exam (i.e. so keep up with past equations).

Based upon the exam that I completed, I walked out and compiled the following:  Of the 250 questions, I answered approximately:

  • 30-35 equations (10-12 ventilation, 7-10 noise, 5 radiation, 1-2 asbestos, 3 parts per million, 2 mg/m3 conversion to ppm)
  • 10 TLV guide questions
  • 15 Toxicology questions
  • 8-10 mold questions
  • 3-5 ethics questions
  • 0 history questions
  • 5-8 workplace hazard questions
  • 3 heat stress questions
  • 5-8 chemistry questions
  • 5 ventilation questions
  • 5 noise questions
  • 5 minimum sample volume (MSV) questions / sampling time
  • 5 fan questions
  • 3 fan type questions
  • & whole lot of other questions that I can not remember exactly  Generally, would you say that the equations you encountered were difficult IH equations?

Examinee:  Absolutely not.  On the exam that I completed, very few of the equations needed were complicated.  Probably the most difficult dealt with contaminant generation and resultant concentration.  Radiation, noise, etc. equations were of the more “simple” variety.  What was the portion of the exam that created the most anxiety?

Examinee:  Actually, you may be suprised.  But, when you complete the exam and you press submit after section 2, the computer delivers a pause of approximately 60-90 seconds.  Very heart wrenching.  At that time, you find out if you passed (or not, I presume).  Any parting words?

Examinee:  Study hard, don’t take it lightly, and have faith!  While only 35-40% on average, in recent years, have passed the exam, you can do it!  Prepare, prepare & prepare some more!  It is well worth it!