- The primary function of a chemical fume hood is to protect laboratory personnel from exposure to hazardous airborne substances.
- It achieves this by containing and removing toxic vapors, gases, and dust generated during the handling of hazardous materials.
- The fume hood works through a ventilated enclosure that draws air away from the user and exhausts it safely outside the building or through appropriate filtration systems.

- Unlike biosafety cabinets that are designed to maintain sterile conditions, chemical fume hoods are specifically engineered for controlling harmful chemical fumes rather than providing a sterile environment.
- Additionally, fume hoods are not intended to serve as heat sources nor are they suitable for chemical storage, as storing chemicals inside can compromise the airflow and safety features.

In summary, the key purpose of a chemical fume hood is to:
- Contain hazardous vapors at the source
- Prevent exposure to toxic chemicals
- Ensure safe ventilation by removing contaminated air from the workspace

This makes option 1 — To contain and remove toxic vapors — the correct answer.

Reference: Laboratory Safety Manual, Volume 3, Chapter 5, Page 102