About CHO Exam Prep
An independent practice platform for the Chemical Hygiene Officer (CHO) exam - real questions across every exam domain, each with a plain-language explanation.
What's on the CHO exam
The Chemical Hygiene Officer (CHO) exam is organized into 18 knowledge domains. It has 150 questions and is completed in 3 hours. Here is what it covers:
- OSHA Laboratory Standard
- GHS labeling and classification of chemicals
- other pertinent regulations
- standard operating procedures
- hazard assessment
- safe work practices
- personal hygiene practices
- general laboratory practices
- special procedures (by hazard class)
- procedures for select carcinogens, reproductive toxins, highly toxic substances, and substances with unknown toxicity
- finding information sources
- control measures, including respirators, laboratory ventilation, and exposure monitoring
- employee training and information
- medical consultation and examination
- emergencies, including plans for power failure, spills, etc.
- laboratory visitors, contractors, maintenance personnel, etc.
- record keeping and documentation
- audits, inspections, and self-evaluations
Every practice question on this site is organized across these 18 domains, so your study tracks the real exam structure instead of guesswork. As you answer, the per-domain analytics surface the areas still costing you points, so your review goes where it moves your score.
What we believe good exam prep looks like
Realistic practice beats passive reading. Every question is written to mirror the style and difficulty of the real exam, with a clear explanation of why the right answer is right and the others aren't.
Your weak spots should find you. Domain analytics, mistake review, and re-drilling are built in, so study time goes where it moves your score.
Pricing should be simple. One payment for a fixed access window matched to your exam date. No subscription, no auto-renewal, and 10 free questions to try before you spend anything.
Get in touch
Questions, feedback, or something not working? Email support@boardmentor.study - candidate messages are read and answered.