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Published on 28/01/2022

Understanding the Dangers of Oxygen

Our latest article gives an insight into the many dangers of oxygen and how  gas detection systems help safeguard  crew amd ship.

It’s often hard to believe that oxygen could cause any harm to our health. Without it, we can’t survive for more than a few minutes, and yet in the wrong hands or as a result of a certain set of unfortunate circumstances oxygen can also prove deadly, especially in confined spaces.

Oxygen can be found in a variety of capacities on board sea-going vessels – so proper management and awareness of the potential risks associated with the carriage and storage of oxygen is key.

Carriage of oxygen on board sea-going vessels

Oxygen on board sea-going vessels has a variety of purposes and it can commonly be found on ships of all sizes and classes. Uses of oxygen at sea include (but are not limited to):

*Welding, steelwork and flame-cutting
*In tanks for deep-sea diving or compression chambers 


*Supplies for medical purposes


*Food preservation and packing purposes

Additionally, the need for medical oxygen on board sea-going vessels to effectively treat sick crew members and members of the public is well-recognised. The International Medical Guide for Ships stipulates that a minimum of two cylinders at 200 bar (8000 litres) should be carried at all times, but many ships choose to carry more than this (flag States require ships to carry 40 litres at 200 bar3 (8000 litres).

The Covid-19 pandemic has compounded this further, with oxygen now being carried on board more ships than ever before.

Why is oxygen on board so potentially deadly?

Oxygen can pose harm to human health and safety in a number of ways. Although the level of oxygen in the environment (usually around 21%) is generally recognised as benign, when pure oxygen is pressurised in gas cylinders it poses a variety of risks.

This is because oxygen behaves differently to other gases and is highly reactive. Pure oxygen, often stored at high pressure, can react violently with materials commonly found on board sea-going vessels such as oil and grease. It can also cause spontaneous combustion when exposed to a variety of other materials. 

Oxygen-fuelled fires are ferocious and more difficult to put out, as they burn hotter than other chemical fires. Alost any material will burn vigorously in oxygen including rubber, silicone and even metals.

Oxygen is so volatile that even in small quantities it poses a risk to health and becomes potentially hazardous. Even an increase of 3% of oxygen in ambient air can pose a significant threat of fire or explosion.

Managing oxygen in a marine environment

Managing oxygen safely in a marine environment involves a number of cautions and the implementation of official guidelines set out by bodies including SOLAS and MARPOL surrounding the use and handling of oxygen.

According to the HSE, the main causes of fires and explosions when using oxygen are:

*Oxygen enrichment from leaking equipment

*Using materials not compatible with oxygen

*Using equipment not compatible with oxygen

*Human error, including incorrect or careless operation of oxygen equipment

Even with careful management, gas detection is still essential to ensure that you crew are covered in the event of an unpreventable oxygen leak.


Like other gases, oxygen is undetectable using our own five senses. Invisible, odourless and colourless, oxygen can quickly gather without being noticed. Unless a leak is identified at the source, it’s impossible to know whether oxygen levels in the air are elevated.

By this time, oxygen can easily flood an area, especially in the confined spaces or poorly ventilated areas crews often operate within. The reactive nature of oxygen means incidents can very quickly occur, even within a minute of an initial leak.

The use of reliable, specialised gas detection equipment is the only way to ensure that your vessels and crew are fully protected against the potential risks associated with carrying oxygen on board.

Fixed gas detectors provide the first barrier of defence against gas leaks, placed throughout the vessel at strategic points to cover potential threats in any area. These gas detectors sound an alarm and raise awareness of a leak in their particular area which can then be appropriately addressed.

Portable gas detectors worn on the person prevent exposure to gases through the course of the working day, ensuring that crew members are protected wherever they may be on board.

Dependable gas detection from Martek Marine

At Martek Marine we’re trusted worldwide to provide specialised safety equipment to the marine industry. Our award-winning gas detection solutions are designed to identify and alert crew members to dangerous levels of numerous gases commonly found on board sea-going vessels including carbon monoxide, nitrogen and of course, oxygen. Our IP67-rated Marine 4 and MED-approved Triple-C gas detectors provide portable, dependable detection of multiple key gases on the go, whilst our fixed MM2000 AND MM5001 models offer comprehensive coverage including a lifetime warranty and unlimited expert support from our experienced team.