Without looking it up can you name the three parts of the OSHA definition for a confined space? If not, that lack of knowledge can be the first common hazard of a confined space.  

Many employees who enter a confined space may not realize how valuable it is to know that vital definition before entering a confined space. What about a permit-required confined space? Can you say what makes a confined space a permit-required confined space? If not, read on. 

The OSHA definition of a confined space is a space that has limited or restricted means of entry, is not designed for continuous occupancy, and is large enough and configured so that a person can enter the space and maneuver well enough to perform tasks. The OSHA definition of a permit-required confined space is one that has the potential to expose personnel to hazards that require controls to prevent injury or death. With that understanding of the definitions of a confined space and a permit-required confined space let’s talk about some of the common hazards that employees face when entering confined spaces. 

One of the more deadly hazards is lack of oxygen in a confined space. Any level below 19.5% is considered dangerous and as the levels continue to drop the danger increases and death can occur in minutes if the oxygen levels are low enough. Common causes of low oxygen levels include hot work like welding or grinding, the oxidation process and bacteria. Exposure to levels at 12% or lower will bring about unconsciousness without warning and so quickly that the employee will not be able to protect themselves or escape.  

While low oxygen levels are bad enough, high oxygen levels can create a different problem altogether. Oxygen levels above 23.5% can create an explosive atmosphere that can ignite with just a spark from a metal tool on metal.  

You can have issues with toxic atmospheres as well. These atmospheres are dangerous because of either the product stored in the confined space or the work being performed while in the confined space. Methane, hydrogen sulfide, and carbon monoxide are just a few of the more well-known gases that can create very hazardous atmospheres.  

Atmospheric hazards can be dangerous and, in some cases, deadly, but they are the only hazards of confined spaces. You still have to pay attention to the common physical hazards such as energized sources like electricity (failing to lockout/tagout), falling into a confined space or objects that fall into a confined space that could strike the employee, engulfment and drowning, and slick and wet surfaces that create slip hazards. Noisy environments, temperature extremes and weather can create hazards as well.  

These common confined-space hazards can lead to serious injuries or even death. The good news is that adhering to a proper written confined-space program can eliminate most of the hazards and provide protection methods for employees who must enter confined spaces.