Why is a dedicated cylinder required for enriched air?

A dedicated cylinder for enriched air is essential primarily to avoid hazardous mixing. Enriched air, or nitrox, contains a higher concentration of oxygen than standard air. Mixing different gases can lead to incorrect partial pressures, which significantly increases the risk of oxygen toxicity when diving. Each gas mixture is designed to suit specific depth limits and conditions. If enriched air is stored in a cylinder previously used for regular air without proper cleaning and purging, residual air can mix with the enriched air, leading to potential hazards underwater. Thus, having a dedicated cylinder prevents any possibility of gas mixing and maintains the integrity of the enriched air, contributing to safer diving practices.