What is a major concern when ventilating an atmosphere that exceeds the upper explosive limit?

When ventilating an atmosphere that exceeds the upper explosive limit, the primary concern is that you risk changing a non-explosive atmosphere into an explosive atmosphere. This is crucial because the upper explosive limit (UEL) defines the maximum concentration of a flammable gas or vapor in the air above which an explosion can occur if an ignition source is introduced. If ventilation is not carefully managed, it could inadvertently increase the concentration of the flammable substance, pushing it above the safe threshold and into a hazardous condition. Proper ventilation must, therefore, aim not only to reduce the concentration of flammable gases but also to maintain a safe balance, avoiding the introduction of additional flammable substances into the environment. This highlights the importance of understanding and monitoring the atmosphere in confined spaces to ensure safety during ventilation processes.