Preparing for the CIH Exam

The BGC Board encourages you to consider your knowledge and experience in light of the CIH Examination Subject Areas (CIH Exam Rubrics) and to assess your recognized strengths and weaknesses. Self-study, specific training, and group discussions are recognized methods of improving perceived weaknesses. However, the Board does not endorse or support specific training courses, study guides, or other activities that are intended or purported to be prepared for its examinations.

Publications and References

BGC examination questions are supported by many sources that reflect the underlying purposes and principles of industrial hygiene, as well as the current knowledge that is expected of the industrial hygienist. The Board suggests that candidates refer to the publications areas of the websites of ACGIH, AIHA, and NIOSH. Candidates also may consult relevant books by such publishers as CRC Press, Lewis Publishers, McGraw Hill, and John Wiley & Sons for lists of available resources.

Sample Questions

The following are provided to familiarize you with the nature and form of questions that may be found in the Board’s examinations. Their subject matter and level of difficulty do not necessarily reflect the content of BGC examinations.

A mixture contains:

50 mL benzene (m.w.=78) v.p.= 75 mm, Hg;  sp. gr.= 0.879
25 mL carbon tetrachloride (m.w. = 154), v.p. = 91 mm, Hg;  sp. gr. = 1.595
25 mL trichloroethylene (m.w. = 131.5), v.p. = 58 mm, Hg; gr. = 1.455


  1. Assuming Raoult’s Law is obeyed, what will be the concentration of benzene in air at 760 mm Hg saturated with vapor of the above mixture?
    1. 3.5%
    2. 4.5%
    3. 5.1%
    4. 9.9%


  2. Which one of the following health effects may be manifested by chronic overexposure to benzene?
    1. Abdominal colic
    2. Bladder tumors
    3. Cholinesterase depression
    4. Leukemogenic cancer


  3. What is the ACGIH Threshold Limit Value for hydrogen fluoride primarily intended to guard against?
    1. delayed lung edema
    2. mottling of tooth enamel
    3. respiratory tract irritation
    4. tubular kidney injury


  4. Under usual operating conditions, what is the static pressure at the discharge side of a fan with 10′ length of discharge duct?
    1. equal to the velocity pressure
    2. less than the atmospheric pressure
    3. equal to the total pressure
    4. greater than the atmospheric pressure


  5. 1,000 cfm is to be drawn into a round, freely suspended duct of 6″ diameter. What is the expected centerline velocity at 4″ outside the duct opening?
    1. 286 fpm
    2. 534 fpm
    3. 765 fpm
    4. 915 fpm


  6. Two separate noise sources of 98 dBA and 96 dBA respectively are installed and operated together. What is the combined noise level?
    1. 99 dBA
    2. 100 dBA
    3. 101 dBA
    4. 194 dBA


  7. A maintenance worker must enter an empty reactor vessel for cleaning, inspection, and lining repair. In the absence of continuous ventilation and testing of the air in the vessel, what should an industrial hygienist recommend?
    1. an organic vapor respirator for the worker and a helper with a lifeline within earshot
    2. performance of the work at night with prior notice to the city’s Emergency Response Unit
    3. flushing the tank with a suitable organic solvent before the worker enters
    4. a SCBA and fixed lifeline for the worker and a helper directly outside the tank


  8. Workers in a brass foundry complain of fever and general malaise on Mondays following a weekend respite from work. What should an industrial hygienist be equipped to obtain upon arriving at the foundry?
    1. blood samples to detect carbon monoxide exposures
    2. air samples to measure exposures to zinc fume
    3. potable water samples to detect PCB concentration
    4. urine samples to measure exposures to lead


  9. What do the radioisotopes 238U, 40 K, 226 Ra, and 235U have in common?
    1. Each is an alpha emitter
    2. Each is a neutron emitter
    3. Each occurs in nature
    4. Each has an analogue normally found in the human body


  10. Why is stack sampling for particulate aerosols done in an isokinetic manner?
    1. to avoid size discrimination of collected particles
    2. to minimize particle deposition in the sampling tube
    3. to collect the respirable-size particles only
    4. to collect samples suitable for direct analysis


  11. Theoretically, what is the minimum number of sound pressure level measurements needed to determine the sound power output from a non-directional noise source in a free field?
    1. one
    2. two
    3. four
    4. eight


  12. What are too many levels of management, chronic and recurring internal problems, and numerous meetings attended by many people typically symptoms of?
    1. poor communications
    2. lack of management training
    3. poor employee morale
    4. a flawed organizational structure