Activity
Saturation Diving
Diving using prolonged pressurised habitation and saturation techniques.
Documents
- 202518 Dec
Dropped object – Bailout cylinder inside diving bell
During saturation diving preparations aboard a vessel, an unsecured bailout set fell approximately 2.5 metres through the bell opening, striking the Transfer Under Pressure door. Nobody was injured; the cylinder was damaged. The flash identifies deficient securing and checks, and records replacement of S-hooks, formal instructions, revised hazard analyses and retraining.
- 202510 Dec
Qualifications of medical personnel on offshore facilities guidance note
Guidance on qualifications and competency assurance for medical personnel at offshore petroleum facilities. It sets out legislative duties, recommended remote healthcare experience and a risk-based approach to staffing. It discusses telemedicine, multiple-casualty resources, diving medical support and additional measures where dedicated medical personnel may be impracticable.
- 20253 Jul
High potential incident: Worker injured when opening a flanged assembly
A worker dismantling emergency shutdown valves on deck sustained a forehead wound when trapped line pressure expelled a gasket. The flash identifies missing pressure checks and monitoring after isolation, alongside water ingress during subsea diving work. Actions included supervised pre-start checks, pressure-checking and venting hold points, and closer line monitoring.
- 202512 Jun
Diving Guidelines - Diving Safety Management Systems and Diving Project Plans
Guidance for preparing diving safety management systems and project-specific diving plans under OPGGS and OEI regulations. It addresses hazard assessment, operational procedures, competence, maintenance, workforce consultation and change management. Emergency provisions include diving bell rescue and evacuation of saturation divers while maintaining pressure, alongside monitoring, investigation and audit requirements.
- 20256 Feb
Saturation diver exposed to chemicals from pipeline
A saturation diver suffered chemical burns after exposure to chemically treated seawater while disconnecting a pigging/flushing hose during decommissioning. The flash identifies uncertainty over flushing and absent engineered barriers. Lessons address understanding pipeline contents, hazard analysis, amended procedures, valve isolation and securing, and reducing exposure through local valves.
- 202412 Nov
Diver exposed to unplanned release of production gas
A saturation diver removing a blind stab from a subsea skid was pushed backwards by released production gas but remained unharmed. The flash identifies unverified isolation, deviation from procedures, inadequate review of task risks and unused ROV tooling. It highlights change management, procedural hold points and reinforcement of stop-work authority.
- 20243 Sep
Near miss: lift bag released unintentionally from crane hook
A lift bag detached from a crane hook at the splash-zone during a saturation dive and floated near a vessel operating in DP mode. Incorrect folding and attachment allowed buoyancy to defeat the self-locking latch. No harm occurred. The flash recommends risk assessment, rigging checks and a tool basket.
- 20243 Jun
Diver’s umbilical trapped during a pipeline flooding operation
A saturation diver’s umbilical became trapped between pipelines when a newly laid line shifted during flooding, interrupting breathing gas. Another diver supplied pneumo gas and helped free the umbilical. The flash examines pipeline configuration, tidal current and umbilical routing, emphasising assessment of existing conditions and management of changing variables.
- 202416 Apr
Main bell wire rope damaged
During bell recovery after a saturation dive, a broken outer wire rope strand lifted a proximity switch bracket into the sheave, damaging the main bell wire. Operators stopped recovery and freed the bracket. The flash describes design shortcomings, sensor relocation, cutting back damaged wire, a witnessed load test and an empty-bell trial.
- 20249 Jan
Diver in the bell hit by falling object
A diver sustained minor head and shoulder injuries when a partially frozen water bottle fell into a diving bell transfer lock after its handle broke. Bottles were being used for cooling without a change risk assessment. Actions included updating change management and risk assessment, and starting arrangements for a bell chiller.
- 20249 Jan
Leak in hot water system for saturation divers
A saturation-diving hot-water unit leaked through locally corroded pipework inaccessible for visual inspection. Diving was suspended because the remaining unit lacked backup. Repairs involved welding a sleeve over the leak and inspecting the other unit. The flash suggests considering wall-thickness measurements of old pipes.
- 202327 Nov
Case study: Saturation diver fatality due to hydrogen sulphide
This safety flash summarises a historical saturation-diving fatality during inspection of a leaking sour-crude pipeline in the Bombay High oilfield. Hydrogen sulphide in the bell caused collapse; the diver subsequently drowned. It discusses possible gas-entry routes, absent gas detection, bell-to-bell rescue and the potential use of ROVs for surveys.
- 202327 Nov
Failure of proportional valve in saturation chamber control
A proportional valve feedback fault interrupted saturation diving, without injury or equipment damage. Automatic safeguards isolated the line and transferred control to a manual valve. Unauthorised dismantling obscured the origin of potentiometer damage; debris was also found. Lessons address manufacturer-led maintenance, critical spares, training and testing before diving resumes.
- 202122 Sep
Failure of in-service saturation bailout bottle
A saturation diver’s bailout bottle lost pressure through wall defects associated with internal corrosion. Similar bottles were quarantined and operations suspended. Moisture was identified as the primary factor, while third-party testing or unsuitable storage was suspected. The flash calls for improved servicing specifications, procedural assurance, receipt inspection, drying and sealing.
- 20212 Jun
Learning outcomes from a real time diver recovery
A saturation diving team reviews recovery of an incapacitated diver into a bell and transfer arrangements through six-metre trunking. Lessons address loose recovery rope, a pocket-mask seal compressed at depth, ROV observation, realistic weighted-mannequin drills, supervisor exercises and proposed greater medic involvement and CPR refresher training.
- 201923 Aug
Accidental activation of emergency stop during saturation diving operations
Accidental operation of unprotected emergency-stop buttons stopped both lubricating-oil pumps and tripped a vessel’s starboard Voith Schneider propulsion during saturation diving. The vessel maintained position and divers were safely recovered without injury. Lessons address button covers, situational awareness, shipboard familiarisation, and more thorough job safety analysis and toolbox talks for routine engine-space maintenance.
- 201925 Jul
Mattress beam landed very close to divers
A mattress lifting beam was lowered dangerously close to saturation divers recovering concrete mattresses on the seabed. The flash identifies lost visual monitoring, poor visibility and failure to stop work. Follow-up checks addressed load separation, diver–crane communications, ROV monitoring, beam visibility aids and incident reporting.
- 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.
- 201820 Jul
LTI: diver injured during water jetting operations
A saturation diver sustained a left-arm lost-time injury during subsea high-pressure water jetting when the gun failed and a component detached. The flash identifies loose locking bolts, inadequate nut retention, unavailable manuals and maintenance shortcomings. Actions included management of change, equipment-condition checks and a dive-team awareness briefing.
- 20173 May
Diving bell TUP O-ring seal damage
A displaced O-ring obstructed diving bell mating on a DSV and was damaged during repeated clamp closures. Trunking pressurisation revealed leakage, prompting inspection and seal replacement. The flash identifies incomplete inspection and difficult access, recommending flange and seal checks between every bell run and describing improved access and inspection recording.
- 20173 Mar
Near-miss: Suspected high levels of CO₂ in diver breathing gas
Two saturation divers working at approximately 92 m experienced breathing difficulties associated with elevated carbon dioxide in reclaimed breathing gas. Saturated absorbent and apparently incorrect analyser calibration were identified. The dive was aborted without further ill effects. Learning focuses on alarm settings, operating manuals, safety-critical competence and contaminated-gas emergency arrangements.
- 201622 Nov
Hand injury during diving operations
A diver sustained two small puncture wounds while recovering a damaged ring joint from seabed mud during riser flange rectification at 169 msw. The joint penetrated his neoprene glove. The flash describes medical treatment and recommends cut- and perforation-resistant gloves and a preliminary hook check before hand recovery of potentially sharp, damaged equipment.
- 20162 Aug
Loss of 3 tonne lift bags owing to equipment failure
During a saturation dive, lifting-link failures released closed salvage lift bags attached to a pipeline. Metallurgical testing revealed strength below the certified rating and weaknesses associated with bent, welded rings. The member concluded that certificates were counterfeit. Remaining bags were condemned and punctured by ROV before diver recovery.
- 20162 Aug
Unintentional release of diving helmet – neck dam/helmet securing arrangements
This flash reports two unintended neck-ring releases on KM17C helmets during saturation diving. It recommends checking equipment interfaces to prevent snagging the release mechanism, maintaining awareness of release potential and reporting further problems immediately. A manufacturer-developed pull pin sleeve may help prevent recurrence.
- 201624 Feb
Near-miss: Fouled diver umbilical
During a shallow-water saturation dive, slack from an extended umbilical was carried into aerated discharge and lifted around a caisson. Platform shutdown allowed its release, and both divers returned safely. The flash highlights overlooked discharge-flow hazards and recommends assessing umbilical length, routing and access during pre-job engineering and risk assessment.
- 201510 Aug
Lost time injury (LTI) and restricted workday case (RWC) following failure of diving bell door system
A diving bell door fell after its hydraulic ram failed, trapping one diver’s feet. A second diver injured his hand during the attempted release using recovery equipment. The flash examines hydraulic pressure, missing maintenance and door securing arrangements, and highlights secondary closure-prevention systems and planned maintenance.
- 201520 Mar
Diver fainted
A tired diver fainted after receiving permission to enter the bell wearing his chemical oversuit. He regained consciousness and the bell was recovered normally. The flash discusses procedural failures, contributory factors identified by the member, and reviews of diving checklists, contamination drills and guidance on precautionary decompression following health issues.
- 201425 Nov
Failure of bell winch clutch coupling during bell recovery
A worn winch clutch disengaged during saturation bell recovery, allowing the partly submerged bell to descend to 10 msw without injury. The flash examines component wear, brake operation and maintenance omissions, and describes coupling visibility improvements, wear measurements, alternating motors and revised inspection and maintenance arrangements.
- 201417 Jul
Bell re-claim failure resulting in minor injury
A saturation-diving incident at 110 msw injured a bellman when a reclaim-line water trap ruptured. An inverted check valve allowed retained exhaust gas to pressurise the trap following a compressor solenoid failure. The flash examines refurbishment errors, filter-change maintenance and inspections that missed the incorrectly fitted component.
- 201430 Jun
Serious engine room fire whilst divers in saturation
An engine-room fire aboard an offshore vessel alongside prompted transfer of saturation divers to a hyperbaric rescue craft. Investigation linked diesel spray ignition to fatigue failure of an insufficiently tightened fuel-filter stud. The flash discusses water-mist suppression, fuel shut-off shortcomings, torque information and separation of filters from hot exhaust surfaces. Nobody was injured.
- 201413 May
First aid injury: Thermos cup exploded after being in hyperbaric environment
A thermal cup returned from saturation through a medical airlock separated violently from its plastic base at surface pressure, causing minor bruising to an assistant life support technician. The flash records the diver’s assumption about pressure differential and recommends drilling such vessels or prohibiting non-venting thermal vessels in saturation chambers.
- 201410 Apr
Decompression illness (DCI) incident during routine decompression of divers from saturation
A saturation diver developed mild decompression illness during planned decompression. Recompression, therapeutic breathing gas and observation resolved the symptoms, with no recurrence during subsequent decompression. Investigators attributed the incident to individual physiology but could not confirm hydration. Recommendations address daily health and hydration checks, bag searches and declaration of personal supplements.
- 201329 Nov
Serious DP diving incident
A diving support vessel lost DP control following RBUS communication failure and drifted 240 m. A diver’s snagged umbilical severed, interrupting gas, hot water and communications. The flash describes recovery and medical monitoring, investigation findings without a definitive jamming cause, a firmware remedy and an improvement project for diving and marine operations.
- 20134 Sep
Near-miss: Un-noticed expiry and deterioration of carbon dioxide-absorbent material
A saturation diver’s acidic taste revealed deteriorated carbon dioxide absorbent in a reclaim tower. Inspection found discolouration and acidic odours in 23 of 27 drums received, with defective seals and inconsistent labelling. The flash describes replacement supplies and new handling guidance, emphasising delivery checks, expiry tracking, stock rotation and disposal of expired material.
- 201330 Jan
Diver emergency decompression following construction barge anchor loss during tropical storm
A construction barge lost its bow/weather anchors during a severe tropical storm while on standby. Nine saturation divers were transferred to a hyperbaric rescue chamber and began accelerated emergency decompression. After tugs restored station keeping, emergency decompression ceased and the divers surfaced safely using their routine profile.
- 201225 Jun
Failure to follow gas quad procedure
A saturation diving incident involved air supplied instead of oxygen after ordering errors and incomplete delivery, connection and gas-analysis checks. Automatic metabolic make-up introduced the incorrect gas into the chamber; no ill effects were found. Actions addressed procedural compliance, authorised delivery verification and portable analyser use before connection.
- 201225 Jun
Near-miss: Saturation diver lost gas supply
A saturation diver conducting pipeline free-span measurements at 100 m lost gas supplies when his umbilical became trapped at the bell interface. He returned unassisted on emergency gas and was unharmed. The flash examines bell movement, restricted access, emergency response, revised procedures and case-by-case assessment of bell positioning for rescue.
- 201229 Feb
Near-miss: Serious subsea burning incident
A saturation diver triggered an explosion while burning holes in a toppled submerged quarters building. Air flushing failed to remove trapped explosive gases from its complex interior. Lessons distinguish vent holes from drain holes, address communication and verification, and recommend alternative cutting methods where the absence of explosive gases cannot be assured throughout the job.
- 201010 Nov
Precautions against jellyfish sting during diving operations
This safety flash addresses jellyfish stings and airborne irritants from contaminated diving suits. It describes tentacle particles remaining after inadequate cleaning and becoming airborne within diving systems. Precautions include task risk assessment, freshwater pressure washing, residue checks, umbilical cleaning, gloves, consideration of over-suits and medical personnel’s awareness of first aid procedures.
- 200919 Jun
Fall from height
A saturation diver fell approximately five feet onto a bell skid while re-entering a chamber using a rotating dogging bar. Removal of the diving bell had reduced edge protection. Recommendations address management of change, correct fixed handholds, personnel awareness and a removable access platform with additional edge protection.
- 200714 Aug
Failure of chamber door spindles and seals
Two successive leaks at chamber-door spindle seals interrupted pressurisation on a diving support vessel following maintenance. Inspection found almost 70% of spindles unserviceable through sealing-area surface damage or bent shafts. The flash recommends identifying spindles and seals as critical components and including their inspection and replacement in planned maintenance.
- 200622 Jun
Trapped pressure release incident
During saturation-system commissioning aboard a diving support vessel, a diver operated toilet valves out of sequence after assuming pressure was absent. A closed external valve left pressure trapped in the holding cylinder. Its release back-flushed raw sewage into the transfer chamber, covering the diver and fracturing the toilet seat.
- 200627 Feb
Hand injury sustained by diver
A saturation diver working at around 70 metres suffered finger crush injuries while disconnecting a chain shackle from a pipeline end manifold pile. Vessel heave tightened the crane-connected chain, trapping his hand against the pad-eye. Treatment continued during four days of decompression; subsequent surgery required partial middle-finger amputation. The company reinforced hand-injury awareness.
- 200529 Jul
Diving bell clamp mating screws
Inspection before saturation diving revealed severely worn bell mating screws and clamp nuts despite apparently acceptable threads. Clamp weight masked the deterioration, making operation appear normal. The member highlighted regular dismantling and thorough component checks with the weight removed from the nuts and screws.
- 20051 Mar
Uncontrolled ascent of lay-down head
A saturation diver working in 120 m of water was struck by an ascending pipeline lay-down head during lift-bag preparations. The flash identifies inaccurate weight data use, inadequate communication, disconnected safety arrangements and insufficient change assessment. Recommendations address measured load weights, lift planning, diving procedures and escalation of safety-device changes.
- 20041 Oct
Possible choking incident – diver’s helmet
During a saturation dive, a detached neoprene helmet comfort pad was caught in the diver’s teeth during inhalation, avoiding choking. Adhesive bonding loss appeared responsible. The manufacturer advised reattachment using approved wet suit cement, while the company recommended close checks of the pad and similar components before every dive.
- 20041 Oct
Uncontrolled decompression during gangway move
A gangway struck a hyperbaric chamber fitting during raising, causing uncontrolled decompression of a man-way trunk and adjacent entry lock. Four divers were in saturation; no injuries were reported. Initial findings identified an unprotected fitting and door misalignment. Recommendations address impact protection, door alignment and management of proposed modifications.
- 20041 Jun
Staphylococcal infection in deep water saturation dive to 200 metres
This flash describes staphylococcal infection affecting seven saturation divers, including one during decompression, while the team worked at approximately 200 metres. The member identified limited isolation capacity, shared chin pads, helmet rotation, high humidity, hygiene shortcomings and insufficiently stringent pre-saturation medicals as factors in its spread.
- 20032 Sep
Near-miss involving diver’s neck dam
A saturation diver discovered missing and loose neck-dam retaining screws during preparations to enter the bell. Inspection identified stripped threads and fitting contrary to company procedures. The flash describes maintenance authorisation and access controls, while clarifying that the fitting method was not necessarily incorrect under other companies’ or manufacturers’ procedures.
- 20031 Jan
Near-miss involving winch failure
A saturation diving bell descended uncontrollably during recovery when trapped hydraulic pressure kept the winch brakes and counterbalance valve open. A cross-haul wire checked the descent and the bell was recovered. Investigation identified incorrect control-system plumbing; corrective work included a bleed line, separation of valve and brake, and valve replacement.
- 20021 Dec
Failure during lift bag operations
A near-miss involved saturation divers moving a 600 kg blind flange with a nominally 500 kg lift bag. The bag and load rose uncontrolled, then the load fell back to the seabed without injury. The flash highlights capacity discrepancies and recommends seabed-anchored inverter lines to restrain and tip bags.
- 20023 Jul
Power management system dynamic positioning (DP) incident
A power management fault interrupted stern thruster operation during saturation diving, causing a DP vessel to leave its intended position. Divers returned to the bell and were recovered. The flash examines inadequate control-card segregation and an unidentified single-point failure, recommending reconfiguration, electrical protection, independent review and FMEA validation trials.
- 20022 Jul
Dynamic positioning (DP) vessel blackout
A saturation-diving vessel suffered a complete blackout and moved some 190 m before control was regained. Divers were recovered without injury. Investigation identified degraded power-management electronics and management-system weaknesses. Recommendations address replacement of the ageing system, UPS maintenance and testing, broader redundancy analyses and revised diving emergency arrangements.
- 1992
Collision between pelagic trawler Antares and trafalgar-class submarine HMS Trenchant with loss of 4 lives
Investigation of the fatal collision between HMS Trenchant and Antares’s trawl gear, with four lives lost. The report examines submarine watchkeeping, passive sonar limitations, warp failures and the probable sinking sequence. It also analyses delayed search activation, deficient liferaft arrangements and diving-supported salvage.
- Undated
Marathon/Technip - Alvheim/Skandi Arctic - Investigation into diving incident
The PSA investigates uncontrolled diving-bell lowering aboard Skandi Arctic during saturation diving at Kneler. Umbilical separation caused pressure loss before the bell reached the water; divers closed leaking valves and restored pressure using stored gas. The report examines handling-system operation, management deficiencies, competence and emergency arrangements, with no known health consequences.