Confined Space Hazards

All the hazards of a normal workspace can also be found in a confined workspace. Confined spaces present additional hazards to workers, as follows:

• Poor air quality
• Possibility of asphyxiation
• Chemical exposures
• Fire
• Process-related hazards
• Physical barriers
• Safety hazards
• Traffic
• Collapse of bulk material
• Flood
• Limited visibility
• Biological hazards

Air Quality

There may be an insufficient amount of oxygen for the worker to breathe. The atmosphere might contain a poisonous substance that could make the worker ill or even cause the worker to lose consciousness.

Asphyxiation

Simple asphyxiants are gases that can become so concentrated that they displace oxygen in the air, which normally has about 21 percent oxygen. Low oxygen levels, at 19.5 percent or less, can cause the following symptoms:

• Rapid breathing
• Rapid heart rate
• Clumsiness
• Emotional upset
• Fatigue

As less oxygen becomes available, the following symptoms appear:

• Nausea
• Vomiting
• Collapse
• Convulsions
• Coma
• Death

Unconsciousness or death may result within minutes following exposure to a simple asphyxiant.

Asphyxiants include the following gases:

• Argon
• Nitrogen
• Carbon monoxide

Chemicals

Chemical exposures due to skin contact or ingestion, as well as the inhalation of toxic air, can be dangerous to workers, especially in confined spaces.

Fire

An explosive or flammable atmosphere may develop within a confined space due to flammable liquids and gases and combustible dust. If exposed to fire or a spark, this atmosphere could lead to a fire or explosion.

Process-Related Hazards

Chemicals can be released within a confined space during some work processes, such as welding. Sometimes supply lines run through confined spaces and can potentially leak their contents into the confined space. When these supply lines contain hazardous materials, such as chemicals, they pose a threat to the worker in the confined space.

Physical Hazards

The following physical conditions in a confined space present potential hazards to workers:

• Noise
• Heat
• Cold
• Radiation
• Vibration
• Electrical exposure
• Inadequate lighting

Miscellaneous Safety Hazards

Workers in a confined space are exposed to other miscellaneous safety hazards, as follows:

• Moving parts of equipment
• Structural hazards
• Entanglement
• Slips
• Falls
• Engulfment

Traffic

Sometimes, work in a confined space requires the use of vehicles, which can pose a risk to workers near the vehicles. Drivers must take care not to run over workers on foot.

Collapse of Bulk Material

Workers in a confined space are at risk of being hit by bulk material that could shift or collapse in the space. Workers can also be trapped by the collapse of material.

Flood

Sometimes barriers are established in confined spaces to keep out free-flowing solids or liquids. If the barriers fail, workers are at risk of drowning and other related perils.

Visibility

Confined spaces often have poor air circulation, which can lead to a buildup of dust or smoke particles in the air. This buildup creates another hazard by reducing visibility for the worker.

Biological Hazards

Because confined spaces typically have limited airflow and reduced ventilation, it is easier for viruses, fungi, molds, and bacteria from fecal matter and sludge to circulate. These biological hazards increase a worker's risk of infection and other illnesses.

To learn more about Confined Space Competent Person/Supervisor visit our Confined Space Competent Person/Supervisor Online Training web page.