California ICC UST Inspector Practice Exam 2026 – Your All-In-One Guide to Exam Success!

An oxygen-deficient atmosphere is characterized by a concentration of oxygen that falls below 19.5% by volume. This threshold is significant because, at levels lower than this, individuals may start to experience symptoms of oxygen deficiency, including impaired judgment, decreased coordination, and increased heart rate. Below 19.5%, the risk of suffocation and serious health issues rises, particularly for individuals engaged in work or activities in confined or enclosed spaces. Consequently, understanding this cutoff helps in assessing safety protocols and ensuring that environments where people work are adequately monitored for oxygen levels to prevent hazardous situations.