Construction Health and Safety Technician (CHST) 2026 – 400 Free Practice Questions to Pass the Exam

The correct answer is that an air-purifying respirator canister designed to filter ammonia gas should have a green color. According to OSHA guidelines and the ANSI Z88.2 standard, different colors indicate the specific type of gas or vapor the canister is intended to filter.

Green signifies that the canister is suitable for absorbing ammonia (NH3), which is commonly found in various industrial settings, including agriculture and refrigeration. When selecting respiratory protection, it is crucial to choose a canister that is specifically rated for the contaminants present in the workplace to ensure the safety and health of the employee.

Understanding these color codes enhances safety by allowing workers to quickly identify the appropriate respiratory protective equipment, thereby reducing the risk of exposure to harmful gases.