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Sam Myers

In multiple industries, work is needed in the dark, secluded corners and crevices of facilities: confined spaces. 

With limited oxygen, limited entry and exit points, and a higher chance of encountering toxic chemicals and gases, a confined space is one of the most challenging and dangerous environments a company can place a worker. 

And if you are not following industry standards and providing proper training, the chances of injury or death skyrocket. We also understand that it can be challenging to keep up with ever-changing industry guidelines and carve out time to train your employees. But safety should never take a backseat, and we’re here to help you create a safer working environment—even in the toughest of conditions.  

By the end of this article, you will better understand the answers to these questions:  

What Is a Confined Space? 


A confined space is a term given to spaces at job sites while, not suitable for consistent human occupancy, are frequently worked in. 

Confined spaces are just large enough for a worker to enter but has limited entry and exit points (almost always one entrance) and are usually accessible only by ladder. Even an open trench could be labeled as a confined space by OSHA because of the minimal ways you can enter and exit.  

Confined spaces can be found in a variety of industries and job sites. Some common examples include:  

  • Silos  
  • Storage tanks  
  • Vaults 
  • Manholes and tunnels 
  • Pipelines  
  • Cellars and storage bins  
  • Hoppers 

Confined spaces can be found at steel mills, large-scale manufacturing facilities, and excavation sites.   

How Does OSHA Classify a Confined Space?  


There are two types of confined spaces: permitted and non-permitted.  

According to OSHA 1910.146(b), a permit-required space has any of the following characteristics:  

  • Contains a hazardous atmosphere 
  • Potential material that can engulf workers 
  • Walls that converge inward or floors that slope downward and taper into a smaller area which could trap or asphyxiate an entrant 
  • Any other recognized safety or health hazard, such as unguarded machinery, exposed live wires, or heat stress 

Permitted spaces have none of the above characteristics and are deemed safer to work in.  

Why are Confined Spaces Dangerous? 



Confined spaces are inherently dangerous work environments, and if organizations do not maintain high safety measures, workers are prone to severe injuries and even death.  

In September 2023, a worker from McClain County, Oklahoma died from asphyxiation while trying to repair a water tank. The asphyxiation, caused by low atmospheric conditions in the tank, also affected two workers who tried to rescue him.  

OSHA’s investigation revealed that the company did not test the space’s atmosphere beforehand. The company was fined $100,000.  

Asphyxiation is just one of the many dangers a worker can encounter in confined spaces, others include:  

  • Toxic chemicals  
  • Toxic gases 
  • Oxygen poisoning – where the body consumes too much oxygen  
  • Fires 
  • Water 
  • Collapsing material 

In some instances, toxic gases from cadmium vapor and hydrogen fluoride may not affect workers until days after they are in the confined space—another reason why testing beforehand is crucial.  

Additionally, all permit spaces must have continuous forced ventilation to avoid asphyxiation and breathing complications.  

What OSHA Standards Oversee Confined Spaces? 


The standards for working in confined spaces can change depending on your industry.  

Because of their unique work environments, the shipyard and construction sectors have their own confined space regulations. But it’s worth noting that the broad requirements for shipyards and construction come directly from OSHA’s General Industry clause (which this article is based on).  

Some of the key standards include:  

OSHA 1910.146(a): 

“Requirements for practices and procedures to protect employees in general industry from the hazards of entry into permit-required confined spaces.” 

OSHA 1910.146 (c)(1): 

“The employer shall evaluate the workplace to determine if any spaces are permit-required confined spaces.” 

OSHA 1910.146 (c)(2): 

“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.” 

OSHA 1910.146 (c)(5)(i)(A): 

“The employer can demonstrate that continuous forced air ventilation alone is sufficient to maintain that permit space safe for entry.” 

What Should You Do Before Entering a Confined Space? 


Before a worker even enters a confined space, you should: 

1.Test the Air Quality 

As the above example shows, failing to test the air quality can have fatal consequences. 

Depending on the size of the space, different gases can lay at different layers, so you can’t assume every layer of the space has the same air quality.  

Let’s say your workers are working in a large tank that was used to store chemicals. While you may test the top half and get a safe reading, your workers can still be exposed to toxic gases at the bottom of the tank.  

2. Have a Stationed Attendant Ready 

The stationed attendant stands outside the confined space and oversees the entrant’s work. They are also there to assist in case an emergency / accident happens.  

3. Make Sure the Entrant Has Proper PPE 

You can’t just go to your local safety supply company and expect them to carry confined-space-ready PPE. PPE used in confined spaces uses specialized material that can be expensive and hard to find. Critical pieces of PPE to have include: 

  • A confined space gas detector (sometimes called a “sniffer”)  
  • Electrical insulated gloves to protect users from shocks and burns  
  • A shield respirator  
  • A safety harness with D-rings attached at the shoulders 
  • Spreader bars that evenly distribute loads

The PPE you need can change depending on the job site. Proper planning will help you have all the proper tools and materials in place to finish a job. Get as much information upfront as you can—find out what hazards are in the environment and what was stored in that space beforehand. 

What Training is Required for Working in Confined Spaces? 


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A worker must take three days of training before entering a confined space for the first time. This training is a mixture of hands-on applications and learning in a traditional classroom environment (analyzing documents, quizzes, written exams, etc.). The training can be in-person or online—depending on the provider. Workers also need to be recertified every two years.  

Because confined space work is so specialized, many companies don’t offer training. According to one of our Fall Protection experts, there may be only around 10,000 certified confined space workers in the United States.  

As a result, you may struggle to find training for your workers compared to other workplace training programs, like fall protection or overhead crane operation. While Mazzella and our training partner Industrial Training International (ITI) do not offer confined space training, here are some companies that offer courses:  

  • MTech Company – Cleveland, Ohio  
  • Johnson Controls  
  • MSA Safety  
  • ClickSafety  

Do You Have a Rescue Plan in Place?  

In addition to proper training, does your organization have a proper rescue plan in place? Are your workers aware of the rescue plan procedures? 

If you don’t have an in-house rescue / safety team, is your local fire department capable of a confined space rescue? Do you have rescue equipment at your facility, like tripods or davits?  

All these questions should have clear answers before a worker enters any confined space. You should also regularly practice your rescue plan to keep workers prepared

How Can You Make Working in Confined Spaces Safer?  


While confined spaces are inherently dangerous environments, proper planning, consistent training, and complying with OSHA and other industry standards go a long way in keeping workers healthy and productive.  

If you would like to learn more about Mazzella’s confined space entry and retrieval products, contact one of our Fall Protection Specialists today.  


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Disclaimer: Any advice, graphics, images, and/or information contained herein are presented for general educational and information purposes and to increase overall safety awareness. It is not intended to be legal, medical, or other expert advice or services, and should not be used in place of consultation with appropriate industry professionals. The information herein should not be considered exhaustive and the user should seek the advice of appropriate professionals.