Confined Space Safety: Why Does the Rescuer Sometimes Die with the Victim?

What is a confined space?

HSE in the UK defines a confined space as any enclosed space where there is a risk of death or serious injury from hazardous substances or dangerous conditions such as lack of oxygen. Obvious examples include storage tanks, silos, reaction vessels, enclosed drains and sewers; less obvious ones include open-topped chambers, vats, furnace combustion chambers, ductwork and poorly ventilated rooms. ^[1] An ordinary space can also become a confined space while work is carried out in it or while it is being modified. ^[1]

The US OSHA standard 1910.146 uses three combined criteria: the space is large enough for a person to enter and work, it has limited or restricted entry or exit, and it is not designed for continuous occupancy. It becomes a “permit-required confined space” if it contains, or may contain, a hazardous atmosphere, material that could engulf an entrant, an internal shape that could trap them, or any other serious hazard. ^[3]

Why does the rescuer die with the victim?

In a 1986 alert, the US National Institute for Occupational Safety and Health (NIOSH) reported that more than 60% of confined space fatalities occur among would-be rescuers, and stressed that a well-designed and properly executed rescue plan is essential. ^[2] HSE likewise notes that deaths include people who try to rescue colleagues without proper training and equipment. ^[1]

The reason is usually that the hazard cannot be seen. The worker who collapsed inside the tank did not trip; more often they lost consciousness from lack of oxygen or a toxic gas. The colleague who jumps in after them out of loyalty enters the same atmosphere without protection and is overcome within moments. A filter mask does not help here, because filtering respirators are not designed for oxygen-deficient atmospheres. ^[5]

So the rule every worker and supervisor must know is this: nobody goes in to rescue someone else unless they are trained and equipped for rescue and working to a plan prepared in advance.

What makes a confined space atmosphere deadly?

HSE lists the main hazards as follows: ^[1]

• Lack of oxygen: from reactions in soil, carbon dioxide produced when groundwater acts on chalk and limestone, cargo reacting with oxygen, or rust inside steel tanks.
• Toxic gases and vapours: these can build up in sewers or leak into pits and trenches.
• Liquids and solids: these can suddenly fill the space or release gas when disturbed, and bridged solids in silos can collapse.
• Fire and explosion: from residues giving off vapour or high concentrations of dust.
• Heat: dangerous build-up of body heat.

The work itself adds hazards, such as welding fumes and solvents, and a restricted entrance makes rescue harder. ^[1] The third edition of HSE’s Approved Code of Practice L101 also draws attention to newer risks, including deliberately created oxygen-deficient environments and fire suppression systems. ^[4]

What is the right order of controls?

HSE explains three duties under the UK Confined Spaces Regulations 1997: avoid entry where possible, for example by doing the work from outside or modifying the space; if entry is unavoidable, follow a safe system of work; and put adequate emergency arrangements in place before work starts. ^[1] The first planning question, then, is not “how do we enter safely?” but “do we need to enter at all?”

What does a safe system of work include?

Elements of a safe system of work as set out by HSE include: ^[1]

• An appointed supervisor who makes sure precautions are followed and checks safety at each stage.
• Suitable workers: experience and training, taking account of physical build, claustrophobia and fitness to wear breathing apparatus.
• Isolation: disconnect mechanical, electrical and pipework connections, and check the isolation is effective.
• Ventilation: natural or mechanical, without petrol-engine equipment, because the carbon monoxide in its exhaust is extremely dangerous.
• Air testing: with a calibrated detector operated by a competent person, and continuous monitoring if conditions may change.
• A rescue harness and line running to a point outside the space, plus reliable communication between inside and outside.
• A permit to work that formally confirms all precautions are in place before entry, including for contractors.

OSHA sets the order of testing: oxygen first, then combustible gases and vapours, then toxic gases and vapours. It treats an atmosphere as hazardous if oxygen is below 19.5% or above 23.5%, or if flammable gas exceeds 10% of its lower flammable limit. ^[3] Never try to improve the air by adding oxygen, as this increases the risk of fire and explosion. ^[1]

How is the rescue plan built before entry?

HSE requires emergency arrangements to be ready before work starts, including: a way to raise the alarm at all times, including nights and weekends; rescue and resuscitation equipment, with training in its use; rescuers who are trained, fit, quickly available and protected from the cause of the emergency; consideration of shutting down adjacent plant; trained first aiders; and informing local emergency services in advance about the specific dangers. ^[1]

OSHA adds practical detail: ^[3]

• The attendant stays outside the space throughout entry and may enter to attempt a rescue only if trained and equipped for it and relieved by another attendant.
• Non-entry retrieval: a chest or full-body harness attached to a line, unless this would increase the risk or not help the rescue, with a mechanical retrieval device required for vertical spaces more than 5 feet deep.
• The rescue team: its ability to respond in a timely manner is evaluated, it practises simulated rescues at least once every 12 months, and at least one member holds current first aid and CPR certification.

Hypothetical example: a worker collapses in a manhole

A maintenance worker climbs down into a drainage manhole to release a valve, then stops responding. A colleague at the top sees that he is unconscious and starts to climb down.

The wrong response: the colleague goes in without breathing apparatus, is overcome too, and the site now has two casualties instead of one.

The right response: the attendant stays out, raises the alarm, starts retrieval using the line attached to the worker’s harness via the rescue tripod, and calls the trained rescue team equipped with breathing apparatus. This is only possible if the harness, line, tripod and emergency numbers were part of the permit before the first worker went down.

What are the requirements in the Gulf?

Requirements differ by country, emirate and sector, so no single system should be treated as GCC-wide. Examples include:

• Sharjah: the code of practice OSHJ-CoP-06, issued by the Sharjah Prevention and Safety Authority, requires a written permit to work where there is a reasonably foreseeable risk of serious injury, including for contractors; oxygen between 19.5% and 23.5%; openings large enough for rescuers wearing breathing apparatus to get in and out; and emergency arrangements in place before work starts. ^[5]
• Abu Dhabi (tourism establishments): Department of Culture and Tourism Circular No. 5 of 2026 requires tourism establishments to keep a register of their confined spaces, put warning signs at entry points, and apply a permit to work system before entry, with atmospheric testing, standby personnel, rescue equipment and suitable protective equipment. ^[6]

Elsewhere, check the requirements of the competent occupational safety authority and of the site owner.

Conclusion

The rescuer dies with the victim when rescue is improvised rather than planned. Avoid entry where you can; if you must enter, do so under a permit, with testing and an attendant outside, and have the harness, line and rescue team ready before anyone goes down, not after someone collapses.