• According to OSHA, a “confined space” has three characteristics: 1) is large enough for an employee to enter fully and perform assigned work, 2) is not designed for continuous occupancy by the employee, and 3) has a limited or restricted means of an entry or exit. A “permit-required confined space” has one or more of these characteristics: 1) contains or has the potential to contain a hazardous atmosphere, 2) contains a material with the potential to engulf someone who enters the space, 3) has an internal configuration that might cause an entrant to be trapped or asphyxiated by inwardly converging walls or by a floor that slopes downward and tapers to a smaller cross section, and/or 4) contains any other recognized serious safety or health hazards. OSHA 29 CFR 1910.146