Justin Tyas examines a case in which two companies were originally fined a total of £640,000 for the deaths of two workers who died while attempting a rescue operation on a barge moored at a salmon farm in Scotland.

A number of people are killed or seriously injured in the UK each year working in confined spaces across a range of industries, including mining, sewage and dock working. Those killed in accidents include people working within the confined space and those attempting rescue from confined spaces without proper equipment and training.

A confined space is a place that is substantially enclosed (not always entirely), and where serious injury can occur from hazardous substances (eg poisonous gases and fumes) or conditions within the space or nearby (eg lack of oxygen).

Confined spaces with limited openings can be fairly easy to identify, and include:

  • sewers

  • reaction vessels

  • silos

  • storage tanks.

Other confined spaces can be less obvious but equally dangerous, for example:

  • ductwork

  • open chambers

  • vats

  • unventilated or poorly ventilated rooms.

Dangers can arise from confined spaces because of issues including:

  • lack of oxygen

  • poisonous gases, fumes and vapours

  • liquids and solids that can suddenly fill the space, or release gases into it when disturbed, eg disturbance of grain which could rapidly fill a silo

  • fire and explosion from excess oxygen and flammable gases

  • dusts in high concentrations

  • residues left in vessels that can give rise to vapours and fumes

  • hot conditions, which can cause an increase in body temperature while working.

Some dangerous conditions may be present in the confined space, but others could arise from the activities taking place, such as gases and vapours produced by welding or through the use of volatile and flammable solvents.

The accident

The fatal accident in question took place on a barge moored at a sea farm and operated by company A, but involved an employee who worked as an engineer for company B. The barge was used to store fish feed, which was kept on deck in containers. Below deck were 11 separate confined chambers. On the centre of the deck was a crane with hydraulics and electrical cabling running below deck. Access below deck and to the chambers was through 11 sealed hatches, each bolted down and with a watertight seal. A problem was identified with the hydraulic crane, and access below deck was required to investigate the problem.

A hissing noise was heard when one of the hatches was opened, and it was decided to wait 15 to 20 minutes with the hatch open so it could vent. Two men then climbed into the chamber, and as one reached the bottom, 8-10 feet below deck, he started to lose consciousness. The second man became dizzy and disorientated on entering the chamber, and immediately climbed back on deck. Another man went to retrieve a respirator, and descended into the chamber to attempt a rescue. He reached the unconscious man and lifted him from the water into a sitting position, giving the thumbs up signal to those above him. He then sat down, stopped responding to those on deck and collapsed. Another employee then fetched a rope and descended into the chamber, but collapsed at the bottom. The three men were removed from the chamber by the fire and rescue service using breathing apparatus. One survived, but resuscitation attempts on the two other men were unsuccessful.

An investigation found the level of oxygen below deck to be at 13% which is significantly below the normal concentration of oxygen in air at 21%. The low level of oxygen was caused by the oxidation of the steel walls in the tank. A relatively small reduction of oxygen in the air can lead to impairment of mental ability, with the effects being extremely rapid with generally no warning to alert the senses. Oxygen concentrations below 16% can lead to unconsciousness and death.

Statutory requirements

Both companies involved in the fatal rescue attempt pleaded guilty to breaching s.2(1) of the Health and Safety at Work, etc Act 1974 (HSWA), which states: "It shall be the duty of every employer to ensure, so far as is reasonably practicable, the health, safety and welfare at work of all his employees."

The following legislation is also relevant to this incident.

The Management of Health and Safety at Work Regulations 1999 require employers to carry out suitable and sufficient risk assessments of work activities. In relation to confined spaces this means identifying the hazards, assessing the risks and determining what precautions to take.

Assessments will normally need to consider:

  • the task and the working environment

  • working materials and tools

  • the suitability of those carrying out the tasks

  • emergency arrangements.

The Confined Spaces Regulations 1997 apply where the risk assessment identifies risks of serious injury from working in confined spaces. They are published with an accompanying Approved Code of Practice (ACOP) L101 Safe Work in Confined Spaces from the Health and Safety Executive (HSE), and apply to all premises covered by the HSWA, with the exception of mines and diving operations.

Key requirements of the Confined Spaces Regulations 1997 include:

  • avoiding entry into a confined space (Regulation 4), eg by doing the work from outside

  • where entry into a confined space is unavoidable, following a safe system of work (Regulation 4)

  • putting in adequate emergency arrangements before the work commences (Regulation 5).

A range of further legislation is likely to be applicable to confined space working, including the Personal Protective Equipment at Work Regulations 1992 (as amended), Provision and Use of Work Equipment Regulations 1998, and the Control of Substances Hazardous to Health Regulations 2002 (as amended).


A number of failings were identified.

  • There was a failure to undertake a suitable and sufficient assessment of the risks involved. In particular, there was a failure to identify the presence of a confined space, and the risks associated with it, including the low level of oxygen.

  • Both companies failed to provide information, instruction, training and supervision to their employees in relation to confined work space and the risk associated with this work.

  • There was a failure to provide plant and a safe system of work to ensure health and safety in relation to both confined spaces and rescue procedures.

Lessons learned

The deaths of the two workers who tried to mount a rescue operation could have been avoided. Suitable and sufficient risk assessment would have identified the presence of the confined spaces (barge chambers), and the dangers involved in the work. This fatal accident demonstrates the need for a suitable safe system of work for working inside the chamber, where entry into the confined space could not be avoided. The risk assessment should have been used to help identify the precautions required to reduce the risk of injury, including air monitoring and testing of oxygen concentration. Only competent workers who were fully trained in confined spaces working and emergency rescue should have undertaken work in the chamber.

Finally, it should be noted that both companies were successful in reducing the size of their fines, which were considered at appeal to be “excessive”. They were reduced to £333,335 and £20,000 respectively.

Last reviewed 23 October 2013