10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The CHO exam has 150 questions and runs 3 hours.
These 10 free CHO questions are organized by exam domain, so you can see how each part of the Chemical Hygiene Officer blueprint is tested. Reveal the answer and explanation under each question.
A research laboratory introduces a new solvent mixture that has not previously been used in the facility. Before employees begin routine work, the Chemical Hygiene Officer should ensure that the laboratory has:
Correct answer: A - A new written Chemical Hygiene Plan section addressing the hazards, controls, and procedures for the work
A technician receives a chemical container labeled with a pictogram, signal word, hazard statements, precautionary statements, and supplier information. Which label element communicates the relative severity level of the hazard?
Correct answer: B - Signal word
During a hazard assessment, a supervisor compares two proposed procedures using the same chemical. Procedure A uses twice the quantity, requires open handling, and produces more airborne contamination potential. Procedure B uses a closed system with a smaller quantity. Which factor most strongly explains the difference in risk?
Correct answer: C - The quantity and exposure potential of the operation are greater in Procedure A
A principal investigator notices unlabeled secondary containers during a laboratory walkthrough. What is the primary safety concern?
Correct answer: A - Employees may be unable to identify chemical hazards and precautions
A laboratory stores incompatible chemicals together on a shelf. Which hazard principle is most directly violated?
Correct answer: B - Chemical segregation based on reactivity and compatibility
A scientist plans to use a known select carcinogen. Which practice is most appropriate?
Correct answer: C - Establish designated procedures and controls
A laboratory worker needs authoritative information about a newly purchased reagent. Which source should be consulted first?
Correct answer: C - The current Safety Data Sheet provided for the chemical
A laboratory must reduce employee exposure to a volatile toxic chemical used daily. Which control represents the preferred approach in the hierarchy of controls?
Correct answer: B - Install an engineering control that captures contaminants at the source
An employee reports symptoms after a documented hazardous chemical exposure. What is the appropriate response?
Correct answer: B - Arrange appropriate medical consultation and evaluation
A small chemical spill occurs inside a laboratory. The substance is known, within the laboratory response capability, and the employee is trained. What is the appropriate initial response?
Correct answer: A - Follow the established spill response procedure and use required controls
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