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Environmental Health and Safety

Confined Space Entry

A confined space is any space that is large enough for an employee to enter, has a restricted means of entry or exit and is not designed for continuous employee occupancy.

A “Permit-required confined space (permit space)” means a confined space that has one or more of the following characteristics:

  • Contains, or has potential to contain, a hazardous atmosphere
  • Contains a material that has the potential for engulfing an entrant
  • Has an internal configuration such that an entrant could be trapped or asphyxiated by inwardly converging walls or by a floor which slopes downward and tapers to a smaller cross-section
  • Contains any other recognized serious safety or health hazard

All of these criteria must be met for a space to be classified as confined space or permit-required confined space. Examples of confined spaces include tanks, pits, certain tunnels, utility vaults and boilers. The physical and atmospheric hazards often associated with confined spaces can cause serious injury or death to workers. The major factors that lead to injuries in confined spaces include failure to recognize and control these hazards, and inadequate or incorrect emergency response.


Scope and Application

The Occupational Safety and Health Administration (OSHA) requirements apply to most activities that require entry into a confined space.

Examples of specific activities include:

  • maintenance, and cleaning of boilers.
  • cutting or welding in confined spaces.
  • telecommunications and electrical utility work performed in manholes and unvented vaults.
  • work in excavations or trenches that could develop hazardous atmospheres.
  • work in sewers, manholes, pits and traps.


Confined Space Program [pdf]
Confined Space Handout [pdf]

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