Confined Space Accident Statistics UK: Deaths and Case Studies

How many people die in confined spaces?

The widely quoted figure of 15 deaths a year comes from an HSE leaflet first published in October 1997. A preserved August 2003 reprint gives the estimate for the UK but does not identify the underlying observation period. The January 2013 replacement explains that workers and would-be rescuers continue to be killed or seriously injured, without supplying an annual number.

The historical estimate describes the scale of the problem at the time of publication. Current HSE accident categories group events by mechanisms such as drowning or asphyxiation, which can occur in several settings. They do not supply a directly comparable annual confined-space total.

What documented UK incidents show

The cases above involve a hospital drain, a waste tanker, a fish-farm barge and two ships. Confined-space hazards can arise during ordinary maintenance and cleaning as well as specialist industrial work.

At Kettering General Hospital, a worker clearing a blocked drain in February 2022 was found unconscious in a manhole and suffered a traumatic brain injury. HSE found that the manhole had not been identified as a confined space and that assessment, training and working methods were inadequate. The trust was fined £480,000 in January 2024.

On Sunbeam in August 2018, an engineer died in a refrigerated seawater tank at Fraserburgh. A refrigerant leak had displaced the air. The MAIB investigation highlighted the importance of recognising enclosed spaces, maintaining equipment and controlling entry.

Why confined-space rescues can cause more deaths

At Loch Creran in May 2009, a worker lost consciousness inside a barge compartment. Two colleagues entered to rescue him and died because of depleted oxygen; the first casualty survived. In the Greenfeeds tanker incident in December 2016, two workers died, including one who tried to save his colleague.

Three crew members died in the Suntis access compartment in May 2014. MAIB considered it likely that the second and third entrants had attempted rescue. These cases demonstrate the danger of successive unprotected entry. They do not establish a national percentage of deaths involving rescuers.

Emergency arrangements need to be planned before entry, with trained people and suitable equipment available. Relying on the emergency services alone is insufficient.

Suntis: oxygen changed sharply with depth

After the Suntis accident, investigators measured 20.9% oxygen at the access hatch, around 10% just below main-deck level and only 5–6% at the bottom of the ladder. A normal reading near the opening did not describe conditions throughout the compartment.

These are measurements from one incident, not entry thresholds. Atmosphere assessment must cover the hazards and locations relevant to the particular space, including toxic and flammable substances as well as oxygen. Conditions can change during the work.

What counts as a confined space?

A confined space is enclosed or largely enclosed and has a foreseeable specified risk, such as fire, explosion, loss of consciousness, asphyxiation or drowning. The definition concerns the conditions inside, rather than simply the dimensions of the opening.

Tanks, sewers and silos are familiar examples, but open-topped chambers can also qualify. A space may become hazardous because of the task, substances introduced, changing liquid levels or gases entering from connected equipment.

Preventing confined-space incidents

HSE’s first principle is to avoid entry where the work can reasonably be done from outside. When entry is necessary, a competent assessment should establish the safe system, including isolation, atmosphere testing, ventilation where appropriate, communication and emergency arrangements.

Supervision, permits and rescue equipment must match the task and hazards. A generic checklist or a single normal gas reading cannot establish that the whole operation is safe.

Frequently asked questions

Where does the figure of 15 confined-space deaths a year come from?

It appears in HSE’s original INDG258 leaflet, first published in 1997 and reproduced in an August 2003 reprint. It is a historical UK estimate. The January 2013 replacement gives no numerical annual total.

Why can one confined-space incident kill several people?

Someone entering to help can encounter the same hazardous atmosphere as the first casualty. Documented UK incidents include deaths during attempted rescues, making planned rescue arrangements essential.

Can an open-topped tank be a confined space?

Yes. A space can qualify when it is enclosed or largely enclosed and presents a foreseeable specified risk, including oxygen deficiency, harmful gases, fire, drowning or engulfment.

Does a normal oxygen reading at the entrance mean entry is safe?

No. Conditions can differ deeper inside or change during work. At Suntis, investigators found normal oxygen at the hatch but only 5–6% at the bottom of the access ladder.