Topic
Oxygen Deficiency
Atmospheres with insufficient oxygen for safe breathing.
Documents
- 2026Feb
CHIRP Superyacht FEEDBACK 11 (February 2026)
Six superyacht reports examine an unpermitted hull repair, a close-quarters encounter, grounding on uncharted coral, fuel-handling failure, hazardous acetone use in a bilge sump and premature anchor release. Commentary addresses reporting culture, collision avoidance, passage planning, fuel purification, respiratory protection limitations and confined-space precautions, emphasising communication and challenges to unsafe decisions.
- 202527 Oct
Japan Transport Safety Board: two confined space fatalities
An IMCA flash summarises a Japanese bulk-carrier incident in which two stevedores collapsed during unloading; one died and one was seriously injured. Low oxygen and elevated carbon dioxide were likely linked to palm kernel shell fermentation. It highlights absent atmospheric testing, inadequate work controls and recommendations for training and cargo risk profiling.
- 202520 Mar
Fatal accident on board bulk carrier Berge Mawson with loss of 3 lives
MAIB investigates three stevedore deaths in Berge Mawson’s coal cargo hold access space. The report considers a fatal atmospheric mechanism highly likely, while noting that medical causes were unconfirmed. It examines pre-entry gas testing, permits, access security, warning comprehension, training and rescue arrangements during cargo operations.
- 202311 Dec
Foundation Food Group Fatal Chemical Release
Investigation of a fatal liquid nitrogen overflow at Foundation Food Group’s poultry plant. A deformed bubbler tube disabled freezer level control and overflow protection, producing an oxygen-deficient room atmosphere. The report examines design dependencies, missing monitoring and ventilation, emergency preparedness, process safety management and regulatory gaps.
- 20237 Dec
Accidental discharge of condensed aerosol fire-extinguishing system on beam trawler Resurgam with loss of 1 life
Investigation of a fatal accidental aerosol fire-extinguishing system discharge during installation aboard Resurgam in Newlyn harbour. It examines electrical commissioning, generator placement, toxic combustion products and impaired escape. Laboratory trials inform analysis of inhalation hazards, while findings address installer competence, regulatory approval, contractor coordination and rescue arrangements.
- 202316 Feb
Fluid Transfer Transport
Hazard alert addressing toxic and flammable vapours, hydrogen sulphide and oxygen displacement during vacuum loading and offloading of produced fluids. It assigns responsibilities to facilities, hauling companies and drivers, covering atmospheric monitoring, training, conductive hoses, bonding and grounding, safe vent discharge and prevention of diesel-engine runaway.
- 202010 Dec
Entry to enclosed space on fishing vessel Sunbeam with loss of 1 life
Investigates a fatal tank entry aboard Sunbeam in Fraserburgh. Leaking refrigerant from corroded evaporator tubes displaced air in a refrigerated salt water tank. The report examines inadequate repairs, non-gastight isolation valves, normalised unsafe entry, absent atmospheric precautions, rescue arrangements and gaps in machinery survey oversight.
- 202025 Aug
High potential near miss: Nitrogen hose failure during transfer of gas
A nitrogen transfer hose detached from its ferrule, releasing approximately 165,000 litres into a pipelay HPU room and reducing oxygen to approximately 17.4%. The degraded hose was absent from the hose register and maintenance regime. The flash recommends rated whip restraints and hose inspections, and records restricted-access signage and low-oxygen alarms.
- 201923 Oct
Use of gas-fired oven cleaning equipment inside vehicles
HSE alerts suppliers, installers and users to hazards of LPG-fired oven cleaning equipment inside vehicles following a van explosion. It sets expected standards for cylinder storage, ventilation, driver separation, ignition control, gas isolation and training, and recommends substitution where reasonably practicable to eliminate or reduce risk.
- 201918 Jun
High potential near miss: Person found unconscious in confined space
A commissioning engineer entered a gas valve unit during nitrogen pressure testing and collapsed. Entry proceeded without a confined-space permit, atmospheric test results or safety watch. Following rescue and CPR, the engineer recovered fully. The flash emphasises authorised entry, atmosphere testing, a safety watch, rescue planning and discussion with a supervisor.
- 201928 May
Partial pressure of oxygen (PPO₂) getting low in bell
During saturation diving at approximately 147 msw, oxygen partial pressure fell in a bell and the main oxygen bottle was subsequently found empty. The flash describes breathing-mix purging, BIBS use and recovery, followed by changes to oxygen make-up responsibilities, panel positioning, valve configuration and buffer-tank connections.
- 201819 Oct
Safety warning about working in enclosed spaces after the loss of 1 life on a fishing vessel
This bulletin presents initial findings from a fatal refrigerated salt water tank entry aboard Sunbeam at Fraserburgh. Testing found severe oxygen deficiency and Freon R22; refrigerant leakage through failed evaporator tubes was considered likely. It discusses hazardous rescue attempts and recommends tank-entry risk assessments, safe procedures and appropriate safety equipment.
- 2018Jun
Safe Work Permits – Understand the Scope of Work — Process Safety Beacon, June 2018
This bulletin examines two nitrogen-asphyxiation deaths during refinery maintenance after workers attempted to retrieve tape from a vessel outside the permitted job scope. It emphasises recognising scope changes, reassessing confined-space entry requirements, communicating hazards and stopping work to consult the permit issuer before undertaking unapproved tasks.
- 201811 Apr
Tank Gauging Hazard Alert
This alert explains how opening storage-tank thief hatches can release concentrated hydrocarbon vapours, creating oxygen-deficient, toxic and flammable conditions. It addresses tank gauging, sampling and fluid handling, outlining exposure assessment, gas monitoring, worker training, remote or closed gauging arrangements, ventilation and stopping unsafe work.
- 201730 Nov
Limitations of Monitors Hazard Alert
This hazard alert explains multi-gas monitor selection and use in oil and gas operations. It highlights hydrogen sulphide monitor limitations, unreliable flammable-gas detection under some atmospheric conditions, and misleading alarm cessation. Guidance covers sensor selection, calibration, bump testing, breathing-zone positioning and immediate evacuation following any alarm.
- 201725 May
Dangerous modifications found within a gas valve unit room
A safety flash describes methane exposure in an LNG carrier’s gas valve unit room following damage to an expansion bellows O-ring. An unauthorised hose arrangement could likely have impaired methane detection. The account highlights ventilation and gas monitoring arrangements, and the US Coast Guard’s recommendation for engineering review and approval of modifications.
- 20167 Jan
High potential near-miss: Poor O₂ content in supplied air – diver temporarily lost consciousness
A diver briefly lost consciousness on a diving support vessel after switching to a breathing-air quad containing around 3% oxygen. Tenders removed his helmet and he recovered. The flash examines supplied-gas quality assurance, an oxygen analyser that failed to alarm, and proposed pre-dive checklist changes to clear residual gas before introducing a new supply.
- 2016
Health and Safety Risks for Workers Involved in Manual Tank Gauging and Sampling at Oil and Gas Extraction Sites
Joint NIOSH–OSHA alert examines toxic hydrocarbon exposure, oxygen depletion and ignition hazards during manual gauging and sampling of production and flowback tanks. It reviews nine fatalities and field exposure measurements, explains filtering respirator limitations, and recommends closed sampling, atmospheric monitoring, exposure assessment, training and emergency arrangements.
- 2016
NIOSH-OSHA Hazard Alert: Health and Safety Risks for Workers Involved in Manual Tank Gauging and Sampling at Oil and Gas Extraction Sites
Joint NIOSH–OSHA alert examines hydrocarbon inhalation, oxygen deficiency and flammable atmospheres during manual tank gauging and sampling. It reviews nine fatalities and field exposure measurements, explains limitations of air-purifying respirators, and recommends closed sampling, exposure assessment, gas monitors, training and emergency arrangements.
- 2015Apr
Safe work in confined spaces
This Approved Code of Practice explains confined-space regulatory duties, identification of specified risks and avoidance of entry. It addresses competent risk assessment, written safe systems, atmospheric testing, ventilation and isolation, alongside respiratory equipment, access design, rescue arrangements, equipment maintenance and role-specific training.
- 2015
Fatalities in Oil and Gas Extraction (FOG) Special Topic Report 2015
NIOSH summarises nine fatalities recorded during 2010–2014 involving crude oil tank gauging, sampling and fluid transfer at well sites. Case narratives examine possible petroleum vapour inhalation, oxygen displacement and reported medical findings. The report describes its surveillance sources and exclusions, while retaining uncertainty about contributing factors and unresolved causes of death.
- 2014Aug
Safety warning regarding entry to confined spaces after loss of 3 lives
This safety bulletin examines three crew deaths following entry into Suntis’s cargo hold access compartment. Initial findings identified severe oxygen depletion, likely associated with timber cargo. It discusses unsafe rescue attempts, breathing apparatus deficiencies, permit-controlled entry, rescue planning and training, and the limitations of emergency escape breathing devices.
- 20125 Nov
Risk of carbon monoxide release during the storage of wood pellets
This safety alert describes fatal carbon monoxide poisoning associated with wood pellet storage, including domestic cases. It explains factors affecting gas production and oxygen depletion in enclosed stores. Suggested precautions cover competent installation and servicing, restricted entry, atmospheric checks, ventilation, risk assessment and warning information.
- 201210 Jul
Confined space entry fatality
A crewman entered a vessel’s cargo tank without breathing apparatus to retrieve sampling equipment and died from oxygen deprivation despite rescue efforts. The flash summarises AIBN findings on the probable tank atmosphere, probable lack of motivation to comply with procedures, and wider non-compliance with confined space entry requirements aboard the vessel.
- 201229 Feb
Major injury suffered in confined space incident
A meter reader sustained severe brain damage after entering a water meter chamber without testing its atmosphere, later measured at six percent oxygen. A colleague attempted rescue but had to withdraw because he could not breathe. The flash stresses atmospheric checks and appropriate confined-space entry and rescue procedures.
- 2011Mar
OCE25 - Well servicing – chemical injection
This offshore COSHH sheet addresses chemical injection during well servicing and coiled tubing operations. It describes chemical exposure and nitrogen hazards, with guidance on planning, protective equipment, line testing, exposure monitoring and dermatitis surveillance. It also covers spill handling, waste disposal, decontamination, training and supervision.
- 2011Mar
OCM1 - Confined spaces
Guidance for offshore dutyholders on preparing method statements for confined-space work. It addresses avoiding entry, competent workers, isolation, ventilation, atmospheric testing and breathing apparatus checks. Space-specific rescue planning includes communication, rescuer capability, resuscitation equipment and practice exercises, with clarification of the offshore status of confined-space regulations.
- 201028 May
Incident during entry to diving bell
A stand-by diver attempted to enter a surfaced diving bell before residual diving gas had been flushed out. Oxygen starvation caused confusion, a fall out of the bell and brief unconsciousness on deck. The flash highlights access control, flushing, atmospheric monitoring and robust confined space entry procedures.
- 20097 Sep
Use of pre-mixed nitrox gases
A diving near miss involved third-party premixed nitrox with incorrect oxygen content. Monitoring detected 32% against an expected 36%, prompting suspension; subsequent testing found approximately 15% in some cylinders. Lessons emphasise supplier quality assurance, analysis before first use, in-line analysers and attention to individual bottles within racks.
- 2008Jul
Safety warning after 3 investigations into entry to enclosed spaces with total loss of 6 lives
This MAIB bulletin examines six deaths across three shipboard enclosed-space accidents, including oxygen depletion associated with corrosion and cargo atmospheres. It discusses failed rescue attempts and breathing apparatus use, and recommends better identification of dangerous spaces, compliance with safe working practices and industry-wide awareness of continuing fatalities.
- 2008
The risks posed by exposure to inerting gases in the open air
This information sheet explains how inerting gases can endanger workers even outdoors, drawing on an offshore maintenance accident. It distinguishes oxygen displacement from toxic effects and describes cryogenic liquid hazards, including risks from water sprays. It recommends assessment of transport, storage and use, and suitable emergency response procedures.
- 20033 Jul
Exposure to CO₂ release from dry ice storage
Two crew members became unwell while stowing refrigerated food aboard a vessel. Dry ice packed with fresh milk released carbon dioxide, displacing oxygen in the enclosed stowage area. The flash describes evacuation, atmospheric testing, job safety analysis, removal using self-contained breathing apparatus and overnight ventilation.
- 2003Jun
Hazards of Nitrogen Asphyxiation — Safety Bulletin - Hazards of Nitrogen Asphyxiation
This bulletin examines nitrogen asphyxiation through workplace incident data and selected cases involving confined spaces, breathing-air mix-ups and attempted rescue. It explains oxygen displacement and discusses continuous atmospheric monitoring, fresh-air ventilation, retrieval arrangements, breathing-air supply integrity, incompatible cylinder fittings and training for employees and contractors.
- 20011 Nov
Need for supplied air in the vicinity of man way during nitrogen purge
During a catalyst change-out, a junior engineer lost consciousness through oxygen deficiency after looking into a vessel manway while nitrogen purging continued during lunch. The company required supplied air near the manway pending further investigation and a chain restricting ladder access during staff breaks.
- 2001Mar
Entry to enclosed space on bulk carrier Diamond Bulker with 1 person injured and loss of 2 lives
Investigates two deaths and one injury during a military search of Diamond Bulker at anchor in Lough Foyle. The report attributes the accident to oxygen depletion and increased carbon dioxide from coal oxidation. It examines entry testing, breathing apparatus, inter-service planning, training and rescue, supported by subsequent atmospheric investigations.
- 20001 Sep
Confined space incident
Two workers died from oxygen deprivation during tank entry on a cargo barge, the second entering to rescue his collapsed colleague. A mandatory entry-permit procedure existed. Recovery involved breathing sets, and the company subsequently required atmospheric testing for all confined-space work, whether or not entry was necessary.
- Undated
Confined Space Entry Program Reference Manual
Reference manual for developing confined space entry programmes under British Columbia’s regulatory framework. It covers space identification, hazard assessment, training, written procedures, atmospheric monitoring, ventilation, respiratory protection, lockout and piping isolation. Standby duties, rescue planning and entry permits accompany sample procedures, a worked permit and ventilation troubleshooting guidance.
- Undated
Enclosed Tank Cleaning: Fatal Facts
An OSHA fatality alert describes two deaths during cleaning and attempted rescue inside a natural-gasoline tank car. Residual vapours displaced oxygen, and the atmosphere was not tested before entry. It outlines permit-controlled entry, atmospheric monitoring, trained attendants, rescue arrangements and respiratory protection, highlighting the failed rescue using an air-purifying respirator.
- Undated
Entry to a confined space on general cargo vessel Baltiyskiy-107 with loss of 1 life
Investigation synopsis of a seaman’s death in a hold access shaft aboard Baltiyskiy-107 carrying timber. Crew attempted rescue using self-contained breathing apparatus. Subsequent atmospheric tests found very low oxygen and high carbon monoxide. These conditions were considered the most probable cause of death; his reason for entry remained unknown.
- Undated
Entry to enclosed space on dry cargo vessel Sava Lake with loss of 2 lives
This investigation examines two crew deaths in Sava Lake’s forward store while approaching the Dover Strait. Oxygen-depleted air almost certainly migrated from a hold carrying ferrous metal turnings through altered ventilation connections. The synopsis discusses cargo identification, carriage restrictions and failures to recognise the store as an enclosed space.
- Undated
Entry to enclosed space on emergency response rescue vessel Viking Islay with loss of 3 lives
Investigation of three fatal chain-locker entries aboard Viking Islay during North Sea rig support operations. Corrosion depleted atmospheric oxygen. The findings address unrecognised enclosed-space hazards, omitted permit measures, unsuitable gas monitoring equipment, unclear entry policy and inadequate training on emergency escape breathing devices, including their limitations during rescue.
- Undated
Entry to enclosed space on passenger cruise ship Saga Rose with 1 person injured and loss of 1 life
An investigation synopsis describes a fatal ballast-tank entry aboard Saga Rose during a Southampton visit. A second bosun entered to check water type; a motorman attempting rescue also collapsed but survived. Corrosion had depleted oxygen. The account examines assumptions about tank contents, permit requirements, enclosed-space procedures and emergency rescue.
- Undated
Hazards of Confined Spaces
This booklet explains atmospheric and physical dangers associated with confined-space entry, illustrated by workplace accident alerts. It discusses oxygen imbalance, toxic substances, explosive atmospheres and machinery hazards, alongside calibrated air monitoring, ventilation, piping isolation and lockout. It outlines the components of a written entry programme, including hazard assessment and rescue arrangements.
- Undated
NIOSH Field Studies, Exposure Assessment, Silica Controls and Gauging and Thiefing
Presentation describing NIOSH field assessments of worker exposure in oil and gas extraction. It examines respirable silica during hydraulic fracturing, dust-source controls and mini-baghouse retrofits, alongside rapid hydrocarbon releases during tank gauging and sampling. Personal sampling, short-task exposure assessment, basin comparisons and closed or remote gauging controls are discussed.
- Undated
Release of cargo vapours on chemical tanker Jo Eik with 2 people exposed to fumes
Investigation synopsis of cargo-vapour exposure aboard Jo Eik at Teesside during mandatory tank pre-washing with portable equipment. Vapours escaped through an open Butterworth hatch and accumulated in an unrecognised enclosed deck area. It examines cargo hazard information, rescue without breathing apparatus, defective washing systems and recommendations for communication and respiratory protection.
- Undated
Toxic fumes from refrigerated sea water tank on pelagic freezer trawler Atlantic Princess affecting 9 people with loss of 3 lives
This inquiry examines three deaths and six injuries aboard Atlantic Princess off Mauritania when contaminated refrigerated seawater tank contents released toxic gas onto the ramp deck. It analyses fish spoilage, tank emptying, cleaning, ventilation and rescue attempts, supported by laboratory simulations, and recommends design improvements, operating procedures, monitoring and crew training.
- Undated
Union Carbide Corp. Nitrogen Asphyxiation Incident — Final Investigation Report
Investigates nitrogen asphyxiation during maintenance at Union Carbide’s Hahnville plant, which killed one worker and seriously injured a contractor. A temporary plastic enclosure trapped nitrogen venting from open process pipework during black-light inspection. The report examines inadequate enclosure procedures, hazard warnings and evaluation of interacting maintenance activities.
- Undated
Valero Delaware City Refinery Asphyxiation Incident — Case Study
This case study examines two contractor deaths in a nitrogen-purged reactor, including an attempted rescue. It analyses permit deficiencies, missing warnings and barriers, and possible oxygen deficiency outside access openings. Lessons and recommendations address pre-job reviews, inert-gas hazard training, breathing equipment and qualified rescue personnel.