Lesson Review: Confined Space Entry Confined spaces can be generally categorized as a space with open tops, a depth that will restrict the natural movement of air and enclosed areas with very limited openings for entry. Hazardous situations within confined spaces can be classified into three areas: • The material stored or used in the confined space; for example, damp activated carbon in a filtration tank will absorb oxygen, and then create an oxygen deficient atmosphere • The activity carried out; for example, the fermentation of molasses that creates ethyl alcohol vapors and decreases the oxygen content of the atmosphere • The external environment; as in the case of sewer systems that may be affected by high tides, heavier than air gases or flash floods. Note the following key points in this lesson: • Types of hazards can be classified into two categories: inherent and induced. • Irritant or corrosive atmospheres can be divided into two groups: primary and secondary. • All employees required to enter into a confined or enclosed spaces should be instructed as to the nature of the hazards involved, the necessary precautions to be taken and in the use of protective and emergency equipment required. • Asphyxiating atmospheres involve the reduction of oxygen in a confined space and may be the result of either consumption or displacement. • When sufficient ventilation cannot be obtained without blocking the means of access, employees in the confined space should be protected by air line respirators in accordance with the requirements of Subpart E of OSHA regulations. It is essential that the employer comply with any specific regulations that apply to work in dangerous or potentially dangerous areas.