Construction Health and Safety Technician (CHST) Practice Test 2026 - Free CHST Practice Questions and Study Guide

The correct answer highlights that free-oxygen respirators are not a typical mode or type of respiratory protection used in the workplace. In occupational health and safety, respiratory protection systems are designed to filter or purify the air, allowing workers to breathe safely in environments where air is contaminated or oxygen is deficient.

Full-face respirators, powered air-purifying respirators, and half-mask respirators are all recognized and widely used types of respiratory protection. Full-face respirators provide a higher level of protection by covering not just the mouth and nose but the eyes as well, creating a full seal against hazardous substances in the air. Powered air-purifying respirators use a fan to pull air through filters, making it easier to breathe, especially in high-contaminant environments. Half-mask respirators offer respiratory protection for the nose and mouth, ideal for many applications where full-face coverage is unnecessary.

In contrast, free-oxygen respirators are not commonly classified with these types of devices. Instead, the term may imply equipment that supplies pure oxygen from a pressurized source, typically used in specific situations, like diving or space missions, rather than general workplace environments. Thus, the classification of respiratory protection effectively excludes free-oxygen respirators from typical usage in