Hazardous Atmospheres In Confined Spaces Employees in many industries enter a variety of confined spaces for inspections, testing, repair or cleaning. A confined space is any area that: (a) has limited openings for entry and exit; (b) may contain or produce toxic air contaminants; (c) has a high concentration of an inert gas; (d) is not intended for continuous occupancy; and (e) may have an oxygen-deficient atmosphere. All such spaces must be analyzed and tested before entry. Workers should also be trained to understand the hazards that may be found in these spaces. A few of the potentially hazardous gases are: Freon®...