Confined spaces can be found in nearly every industry, from manufacturing to utilities and food processing. While these spaces are often small parts of the workplace, they account for a surprisingly high number of serious injuries and deaths.
Let’s take a closer look at how often these incidents happen, why they’re so dangerous, and what the data tells us about the risks involved.
What Is a Confined Space?
A confined space, according to OSHA, is an area that:
- Is large enough for a worker to enter and perform tasks
- Has limited ways to enter or exit
- Is not designed for regular or continuous work
Examples include tanks, silos, tunnels, pipelines, vaults, and manholes. These spaces are not always dangerous on the surface, but they often hide risks that can turn deadly very quickly.
Confined Space Deaths: By the Numbers
From 2011 to 2018, the U.S. recorded 1,030 worker fatalities caused by confined space incidents.
That’s an average of 129 deaths every year, or roughly 2–3 fatalities every week. These deaths occurred across various industries, not just construction. In fact, many of them happened in:
- Manufacturing
- Utilities
- Mining
- Chemical plants
- Wastewater treatment facilities
During this period, confined space deaths made up about 2% of all workplace fatalities, which may seem small, but this is a disproportionately high number when you consider how few workers regularly enter confined spaces compared to the general workforce.
Top Causes of Death in Confined Spaces
Confined spaces are dangerous because of what they hide. Here’s how fatal incidents break down by cause:
- 56% involved toxic atmospheres or oxygen deficiency
(e.g., exposure to hydrogen sulfide or lack of oxygen) - 20% were due to engulfment hazards
(e.g., being trapped by water, grain, or sand) - 11% involved falls, crushing, or being struck by objects
- The rest involved fires, explosions, and other physical hazards
Many workers died within minutes of entry. In some cases, they were unaware of the risk because the air inside looked normal. But hidden gases or lack of oxygen made the space lethal.
Who Are the Victims?
Based on national data:
- 88% of victims were men
- Most victims were aged 25–44
- Many incidents happened during routine maintenance or repairs, not emergency work
One of the most shocking facts: about 60% of confined space deaths are would-be rescuers. These are usually coworkers or supervisors who try to help without proper training or equipment, and become victims themselves.
Fatality Rate and Risk Level
The fatality rate for confined space work in general industry is estimated between 0.05 and 0.08 per 100,000 workers. This is considered high compared to other types of workplace risks.
The reason is simple: confined spaces contain multiple hidden dangers, including:
- Lack of oxygen
- Toxic gases (like carbon monoxide, ammonia, or hydrogen sulfide)
- Flammable vapors
- Mechanical hazards (e.g., moving parts or mixers)
- Risk of engulfment
- Poor visibility
- Limited room for movement or escape
Many of these incidents occur in everyday tasks like:
- Cleaning inside tanks
- Repairing valves in underground vaults
- Inspecting pipelines
- Servicing boilers or chillers
Trends in Confined Space Safety
Even with OSHA standards in place, confined space incidents continue to happen year after year. While fatalities have stayed between 88 and 166 annually, this suggests that improvements are needed in:
- Training for general industry workers
- Permit systems and hazard evaluations
- Use of monitoring equipment
- Rescue planning and drills
In many fatal cases, the space had no air monitoring or the workers were unaware of the danger. In others, workers had not received proper confined space training.
Industry Breakdown
Let’s look at how different sectors are affected:
Manufacturing
Many manufacturers use large tanks, hoppers, and ducts. Workers often climb inside for cleaning, repairs, or inspections. Risks include:
- Dust explosions
- Lack of airflow
- Residual chemicals
Utilities
Electric, water, and gas utilities have underground vaults and storage tanks. Fatalities in this sector often involve:
- Low oxygen
- Exposure to hydrogen sulfide
- Confined electrical spaces
Food and Beverage
Food plants use mixers, silos, and kettles that need regular cleaning. Hazards include:
- Steam burns
- Moving blades
- Exposure to cleaning agents
Chemical Plants and Refineries
These sites pose some of the highest confined space risks, with dangers from:
- Flammable vapors
- Toxic chemicals
- High-pressure equipment
Why Do So Many Rescuers Die?
It’s human nature to want to help someone in danger. But in confined space incidents, this urge often turns deadly.
About 6 out of 10 confined space deaths are of people who tried to save a coworker without thinking of the risks.
These would-be rescuers often:
- Enter without testing the air
- Lack proper breathing gear
- Have no harness or communication line
- Don’t know how long it’s safe to stay inside
In many cases, rescuers die within seconds of entering the same toxic or low-oxygen environment.
How Can Companies Reduce These Numbers?
To reduce confined space incidents, employers in general industry must:
- Identify all confined spaces in the workplace
- Classify spaces as permit-required when needed
- Train workers before allowing entry
- Use proper gas detection equipment
- Develop written entry procedures
- Plan for non-entry rescue whenever possible
- Hold drills for emergency teams
This isn’t just good practice, it’s required by OSHA under 29 CFR 1910.146.
Conclusion: Data Doesn’t Lie, Confined Spaces Are High Risk
While confined spaces may only make up a small part of the work environment, the risk they pose is large. With an average of 129 deaths every year, and a high number of injuries, confined space work should never be treated lightly.
From manufacturing floors to water treatment plants, these spaces are filled with hidden threats, gases you can’t see traps you can’t predict, and accidents that can happen in seconds.
But with the right steps, like training, air testing, communication, and rescue planning, these deaths can be prevented.
