The Gide to Occupational Health Exams

The CIH Summary
What: Tests to ensure competence that lead to certification
Who: Candidates who wish to be certified.
Where: The CIH exam is offered at either Prometric exam locations in North America or internationally, based on the number of applicants outside of North America. OHST/CLCS exam is offered globally as Pearson Vue testing centers.
When: The CIH exam is offered either during the spring window, April 1st-May 31st or during the fall window, October 1st-November 30th. The OHST/CLCS exam is offered year-round.
How: Multiple choice and completion
Type: Both are computer-based, except for the CIH exams offered outside of North America, which are paper-based.
Why: Certification sets individuals apart and marks their ability to anticipate hazardous work conditions that could create health problems for workers or the environment.
Time: 8 hours for the CIH; 4 hours for the OHST
Language: English
Preparation: Practice tests are available.
Cost: Exam fees range from $50 to $1,995.

By Kara Arnold, Tests.com Contributing Writer

Industrial hygienists, occupational health and safety technologists and loss control specialists help to ensure safe working conditions in employment locations throughout the world. Certification is one way people in such occupations can prove their knowledge and skills. The Certified Industrial Hygienist (CIH) exam and Occupational Health and Safety Technologist (OHST)/Certified Loss Control Specialist (CLCS) exam offer certification for professionals.

Certified Industrial Hygienist Exam

Industrial hygienists evaluate work conditions to anticipate and prevent adverse employee health conditions. Certification from the American Board of Industrial Hygiene (ABIH) demonstrates success and professionalism in the field, and some CIHs reap immediate rewards such as higher pay and career advancement opportunities. While many industrial hygienists elect not to become certified, some employers require certification for employment.

To be qualified for ABIH certification, a candidate must have a BA/BS in science, math, engineering, science-based technology or related field. Higher education courses in IH fundamentals, measurements, controls and toxicology are also required, as is four years of professional IH experience. (In some cases, a graduate-level degree may count toward professional experience.)

The eight-hour, multiple-choice exam includes topics such as:

  • Air sampling and instrumentation
  • Analytical chemistry
  • Basic science
  • Biohazards
  • Biostatistics
  • Community exposure
  • Engineering controls and ventilation
  • Epidemiology
  • Ergonomics
  • Ethics
  • Health risk analysis and hazard communication
  • Ionizing and non-ionizing radiation
  • Noise and vibration
  • Non-engineering controls
  • Program management
  • Thermal stressors
  • Toxicology
  • Work environments and industrial processes

Individuals must register for the examination with ABIH by February 1 for the spring exam and August 1 for the fall exam. Applicants must send in transcripts, professional references and detailed experience descriptions with their applications.

Once exam candidates are approved to test, they may register online or by calling the Prometric Contact Center at 800-800-1123. Those outside of North America may schedule via Prometric’s website or by contacting their regional registration center.

The exam is offered via computer in North America at Prometric testing locations, while paper exams are administered outside of North America where sites are determined by the number of applicants and available proctors.

Immediately after the exam, the examinee will learn his/her preliminary pass/fail status and will receive official results in writing about four weeks later. It is not necessary to pass each individual content domain; however, examinees will receive a report showing their scores in each individual subject area. According to ABIH, a passing exam score is the total number of questions answered correctly, and there is no penalty for incorrect answers. Individuals may not retake the CIH exam within 3 months of taking the examination. This means those that fail in the spring must wait to apply for fall examinations.

Exam fees are as follows:

  • Application fee - $150.00
  • Reapplication fee - $75.00
  • Examination fee - $375.00
  • Annual renewal fee - $100.00
  • Late renewal fee - $25.00

Occupational Health and Safety Technologist/Certified Loss Control Specialist Exam

Occupational Health and Safety Technologists (OHST) and Certified Loss Control Specialists (CLCS) assess worksites to identify potential hazards, evaluate control measures, investigate incidents, maintain and evaluate incident and loss records and prepare for emergency response, according to the Council on Certified Health, Environmental and Safety Technologists (CCHEST).

Certification is a designation that proves competence in the field. As with the CIH exam, an examination is required for an individual to become certified.

OHST and CLCS certification qualifications include:

  • Working part-time or full-time in occupational health or safety
  • Five years of experience in occupational health or safety
  • Successful completion of the OHST/CLCS exam

(Health and safety college courses or an associate degree or higher may replace some or the entire work experience requirement.)

Candidates must pass the computer-based OHST/CLCS exam to receive the Associate Occupational Health and Safety Technologist (AOHST) or Associate Certified Loss Control Specialist (ACLCS) distinction.

The four-hour OHST/CLCS examination consists of 200 multiple-choice questions with four possible answers. The exam score is determined by the number of correct answers.

Some questions involve computations, and the testing center provides necessary materials to complete these calculations by hand.

Test questions include topics such as:

  • Worksite assessment
  • Hazard control and loss prevention
  • Verification
  • Disaster planning and emergency response
  • Professional responsibility

OHST and CLCS exams vary only in context, since CLCS items are oriented toward insurance loss control work.


Candidates must apply for examination authorization by filling out the application, experience and reference forms, all available at CCHEST’s website. Applicants must choose either OHST or CLCS and take the respective exam; however, the application and exam registration process are the same. The examinations cover the same knowledge and successful candidates may switch their OHST title to CLCS title and vice versa twice, if necessary, by filling out request forms available at the CCHEST website.

Once candidates receive exam authorization, they may schedule their examination. The exam is offered globally at Pearson VUE test centers, which are typically open every business day and on some weekends and holidays.

Associated OHST/CLCS certification and exam nonrefundable fees include:

  • Application fee - $125
  • Computer-delivered examination authorization fee for inside US or Canada - $265
  • Computer-delivered examination authorization fee for outside US or Canada - $365
  • Paper examinations taken at special locations (e.g. US military DANTES sites) - $1995
  • OHST/CLCS annual renewal fee - $105
  • AOHST/ACLCS annual renewal fee - $95
  • Examination authorization extension - $50

Getting ready for the CIH or OHST/CLCS exams? Take a look at the CIH Exam Directory and the OHST Test Directory.