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Confined Spaces: Top 4 Hazards You Aren't Aware Of

By Gina Gould
Published: May 12, 2021
Key Takeaways

Assumptions, complacency, and lack of preparation are serious dangers when it comes to confined space entry.

Caption: Confined space Source: ultrapro / iStock

The work performed in confined spaces is often some of the most dangerous that employees will perform in their entire careers. There are many significant hazards associated with this type of work, including:

  • Toxic atmospheres
  • Oxygen-rich environments
  • Oxygen-deficient environments
  • Flammable atmospheres
  • Free-flowing liquids or solids
  • Excessive heat
  • Excessive noise
  • Inadequate lighting
  • High concentrations of dust

But confined spaces include several other risks and hazards that are worth discussing, too. These are four hazards associated with confined space work you might not be aware of but that should be taken seriously.

1. Not Being Adequately Prepared

Most confined space incidents can be attributed to at least one of the following: a lack of recognition, testing, evaluation, or monitoring.


Many post-accident investigations reveal that employees weren't even aware that they were working in a confined space. Testing and evaluation are not always conducted. And the ongoing monitoring of employees working in a confined space is often overlooked.


It's essential for workers to be trained on how to recognize confined spaces and their hazards. OSHA defines a permit-required confined space as having one or more of the following characteristics:

  • Contains or has the potential to contain a hazardous atmosphere
  • Contains material that has the potential to engulf an entrant
  • Has walls that converge inward or floors that slope downward and taper into a smaller area which could trap or asphyxiate an entrant
  • Contains any other recognized safety or health hazard, such as unguarded machinery, exposed live wires, or heat stress

Workers must understand that confined space work can lead to serious injury or even death if preventative measures are not taken.

Additionally, OSHA standards require employers to provide training "so that all employees acquire the understanding, knowledge, and skills necessary for the safe performance of the duties assigned for confined space work."


Before entry, all permit-required confined spaces must be tested by a qualified person to determine whether the atmosphere within the space is safe.

Tests should be conducted for oxygen level, flammability, and any other known or suspected toxic substances. A simple handheld gas monitor can be used to conduct these tests.


Employees must evaluate the confined space to determine the following:

  • Whether or not it is considered "permit required"
  • Which hazards are (or might be) present
  • Which methods to use for isolating the space from mechanical and/or electrical hazards
  • Whether or not lockout/tagout will be required
  • Whether or not there is adequate ventilation of the space
  • Determining if the use of safety lines attached to the person working in the confined space will be required
  • Which personal protective equipment will be necessary (respirators, etc.)
  • Whether any special tools will be required to complete the work safely
  • Which communications system is to be used

This evaluation should be done by a competent person, usually the supervisor. But all employees should be adequately trained to also make the same types of evaluations.


The confined space needs to be continuously monitored to determine whether the atmosphere has changed due to the work being performed. Again, a simple gas detection monitor can be used.


(Learn more in Gas Monitoring - Some Jobs Couldn't Be Done Without It.)

A trained "confined space attendant" must also monitor the space whenever an employee is working inside.

The attendant has very specific duties that they must follow. Primarily, monitoring who goes in and out of the space, maintaining communication with those inside, and initiating appropriate rescue procedures if needed.

2. Complacency and Not Following Procedures

Even if employees are adequately trained and prepared, complacency can still become a problem.

Workers may choose to forgo using their safety equipment, including respirators, harnesses, retrieval lines, and other PPE that could save their lives in an emergency situation.

They also may choose not to fill out the confined space paperwork. Don't forget - a "permit-required" space actually requires a permit! Workers sometimes view this step as unnecessary or time consuming.

Another example of complacency is employees not taking their gas detection monitors seriously when they detect a signal. Procedures typically require employees to evacuate the space if an alarm goes off, but some employees will choose to ignore them instead.

This usually comes down to training and mindset. Employees might believe that if they cannot see or smell danger, everything must be fine. Or, they want to get the job done so badly that they assume there is time to hurry up and finish before any real problems can arise.

Make sure your employees are following procedures and avoid issues of complacency.

3. Not Implementing a Rescue Plan

Safely rescuing workers from a confined space situation requires careful thought and consideration. Sadly, NIOSH estimates that over 60% of all confined space deaths include would-be rescuers.

Therefore, the employer must establish and implement an adequate rescue plan that protects all employees, including rescuers.

OSHA standard 1910.146(d)(9) states that all "permit-required spaces must identify procedures for summoning rescue and emergency services, for rescuing entrants from permit spaces, for providing necessary emergency services to rescued employees, and for preventing unauthorized personnel from attempting a rescue."

These requirements must be outlined in the employer's written confined space program.

(Find out What Your Confined Space Safety Program Needs to Cover.)

Keep in mind, that simply having a written procedure is not enough. In order for the rescue plan to be effective, workers must participate in ongoing drills and training.

4. Making Assumptions About Confined Spaces

An additional hazard that you might not be aware of is employees making assumptions about confined spaces.

For instance, installing signage on their permit-required spaces can be hazardous. Why? Because workers will begin to assume that only the areas with these signs are considered confined spaces.

While signage can be a good way to alert employees to potential hazards, the reality is that not all of the confined spaces will be equipped with a sign. And the signs your workplace does have can deteriorate and become illegible, fall of and not get replaced, or never be installed in all the right areas in the first place.

And in fact, signage isn't technically required by the OSHA standard.

The regulation states if the workplace contains permit spaces, the employer shall inform exposed employees, by posting danger signs or by any other equally effective means, of the existence and location of and the danger posed by the permit spaces.”

When employees assume that confined space hazards exist only where the signs are, they may not follow the appropriate confined space policies and procedures when working in unmarked areas.

Another example of a dangerous assumption is that all confined spaces are in fully enclosed areas. This simply isn't true, and workers who make this assumption are putting themselves at risk.

Examples of open-top spaces include aeration basins at a wastewater treatment plants, open top valve pits, tanks, and other similar structures. In most cases, these will be considered permit-required spaces based on OSHA's current definition. Proper procedures must be followed.

Confined Space Safety

Nearly 1.6 million workers enter confined spaces each year. Because the hazards associated with this type of work can be so dangerous, it's important for both the employees and the employer to take the necessary steps to prevent future deaths and injuries.

In fact, OSHA estimates that if employers were to fully comply with the confined space safety standards, 53 deaths, 5,000 lost days, and 5,700 other accidents would be prevented annually.

Many of the injuries and fatalities related to confined spaces occur simply because employers and their workers failed to recognize, plan for, and control the hazards related to this type of work. But with proper compliance and due diligence, you can help protect your employees from the hazards of confined space work activities.


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Written by Gina Gould | Content Writer & Marketing Strategist

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Gina is a freelance writer and content marketing strategist. She primarily works with B2B companies in the safety and industrial markets.

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