Safety Insights Paper - Enclosed Space Entry

This RightShip Insights series provides industry partners with key learnings from industry incidents, identified gaps and leading practices to improve standards and mitigate risk.  



This paper discusses issues around Enclosed Space Entry and: 

  • Observations on preventable fatalities. 

  • Identified gaps and what good managers do to mitigate risk to seafarers; 

  • Where to find further information. 

Don’t be the Next One… 



In addition to the case studies,  

  • May 2019, General Cargo Vessel, one crew member fatality inside cargo hold after losing consciousness due to inhaling toxic gases and falling from height. 

  • July 2019, Chemical/Product Tanker, two crew lost their lives due to poisoning by toxic gases inside cargo tank. 

  • July 2019, Chemical/Product Tanker, three crew members collapsed inside a cargo tank. Two recovered and one fatality. 

  • July 2019, Chemical/Product Tanker, one crew member fatality due to unauthorized cargo tank entry. 

  • September 2019, Bulk Carrier, one fatality inside an enclosed space adjacent to cargo hold. 

  • September 2019, Bulk Carrier, two crew members lost their lives onboard. The first occurred inside the lower duct and the second occurred due to carbon monoxide poisoning during the search and rescue operation. 

  • January 2020, Bulk Carrier, one crew member fatality in cargo hold due to gas intoxication. 

  • February 2020, Crude Oil Tanker, once crew member died due to inhaling poisonous gas and falling from height. 

  • March 2020, Open Hatch Cargo Ship, one crew member lost their life inside cargo hold loaded with wooden logs. 

  • August 2020, Bulk Carrier, one crew member died inside cargo hold loaded with coal cargo due to asphyxiation. 

  • September 2020, Bulk Carrier, one fatality inside cargo hold full of scrap metal.  

  • March 2021, Bulk Carrier, two people died inside cargo hold due to asphyxiation. 

  • March 2021, Bulk Carrier, one port worker collapsed inside cargo hold due to asphexiation and was rescued but lost his life at the hospital. 

  • April 2021, Bulk Carrier, one crew member died inside cargo hold (full of coal cargo) due to toxic gas inhalation.  

  • June 2021, Chemical/Product Tanker, one crew member list his life inside an enclosed space (single man entry).  

  • July 2021, Bulk Carrier, one crew member died due to poisoning by fumigants. 

  • August 2021, General Cargo Vessel, one fatality inside cargo hold due to hypoxic asphexia.  

  • May 2022, Bulk Carrier, two crew members collapsed inside cargo hold due to fumigant gas inhalation. One rescued and one died. 

  • May 2022, Bulk Carrier, two port workers suffocated inside cargo hold. 

  • June 2022, Bulk Carrier, three persons died inside cargo hold due to gas asphyxiation. 

  • June 2022, Chemical/Product Tanker, two fatalities inside cargo tank during tank inspection.  

  • July 2022, Chemical/Product Tanker, one crew member died inside cargo tank, a second hospitalized. 

  • July 2022, Chemical/Product Tanker, one crew member lost his life inside cargo tank.  

  • August 2022, Chemical/Product Tanker, one crew member died inside cargo tank. 

  • August 2022, Bulk Carrier, one fatality inside cargo hold bilge due to toxic gas inhalation (previous cargo coal). 

And it continues…. 



RightShip assessed a selection of 360 incidents, resulting in 385 fatalities, that had occurred since 2019. Of these, 31 happened in enclosed spaces resulting in 39 lives lost. These tragic incidents could have been avoided, if certain preventative or mitigating controls had been in place.  

Below are three case studies provided to illustrate how rapidly these occur.  

Note: RightShip makes no reference to companies or vessels involved in cases described. 


Case 1 - H2S Intoxication within cargo tank  

The vessel was loaded with crude degummed soybean oil. After discharging, vessel drifted for 8 days. During this time, all tanks were washed, except cargo tanks 4 Port and Starboard where the residues/slops were accumulated. Once the voyage orders were received, the crew continued tank cleaning.  

After washing and mopping operations were carried out in cargo tank no. 4 Starboard, the 4 Port cargo tank washing water was discharged to the sea. Entry into the cargo tank was scheduled for after discharge and freshwater wash completion. There was no issued instruction to the deck crew regarding tank entry, cleaning, or mopping. 

At 5:30 PM, Able Bodied Seaman no. 1 (AB1) notified the Chief Officer that he saw the Bosun and Able-Bodied Seaman no. 2 (AB2) lying on the floor of the 4 Port cargo tank. He added that he suspects they may have fallen into the tank. A general announcement was made, and the Chief Officer arrived at the scene joined by other crew members. The Master arrived few minutes later accompanied by the Chief Engineer. 

They witnessed Able Bodied Seaman no. 1 (AB1) lying on the tank floor next to the Bosun and Able-Bodied Seaman no. 2 (AB2). It was evident that he attempted to rescue them without waiting for assistance and/or evaluating the situation. The Master, ignoring the crew's attempt to stop him, rushed into the tank without Personal Protective Equipment (PPE), where he immediately collapsed. The rescue team commenced rescue operation following relevant procedures and lifted the casualties out of the tank. 

On their arrival, the shore medical/rescue team completed atmosphere measurement and observed the presence of Hydrogen Sulphide (H2S) inside the tank. Upon their examination of the casualties, the Master, Bosun, and Able-Bodied Seaman no. 2 (AB2) were pronounced dead. Able Bodied Seaman no. 1 (AB1) was evacuated to a shore hospital. 

The autopsy revealed pulmonary oedema in all casualties, a common result of exposure to high concentrations and intoxication of H2S. Furthermore, toxicology revealed lethal levels of thiosulfate, which resulted from metabolism of H2S.  


Case 2 Asphixiation within cargo hold 

The vessel arrived at her nominated discharging port’s outer anchorage area partly loaded with Silver concentrate (Hecla Silver) inside cargo hold 2, and bulk concentrate inside cargo hold no. 1 and cargo hold no. 4.  

That morning, the vessel’s Chief Mate along with Able Bodied Seaman no. 1 (AB1) conducted daily deck maintenance checks. They started at the Bosun store, before moving to the cargo holds. The Chief Mate intended to enter cargo hold no. 2 to check the hatch cover watertightness. Able Bodied Seaman no. 1 (AB1) was ordered to open the manhole for ventilation. After 30 minutes the Chief Mate went down the ladder through the open manhole while Able Bodied Seaman no. 1 (AB1) remained outside.  

A few minutes later, AB1 shouted out to the Chief Mate a couple of times, yet there was no response. Able Bodied Seaman no. 1 (AB1) then decided to enter cargo hold no.2 to check on the Chief Mate. While climbing down the ladder, about two metres into the cargo hold, he realised it was difficult to breathe. He saw the Chief Mate lying unconscious on the second platform. Able Bodied Seaman no. (AB1) exited the cargo hold, went back to the accommodation, and called for assistance.  

The Master and crew members gathered on the poop deck to conduct the rescue operation. Crew members commenced opening the cargo hold hatch covers. Which took longer than expected due to the pre-tightened securing cleats. The hatch cover was opened, and the Chief Mate was recovered, however with no pulse. Crew performed CPR close to 1 hour with no response and the Chief Mate was pronounced dead. 


Case 3 Three fatalities during cargo hold sampling 

This tragic incident took place onboard a bulk carrier berthed at port. The ship arrived with a cargo of wheat bran pellets. The receiver’s representative requested the vessel provide samples from all holds. The Chief Mate along with Third Officer and Able-Bodied Seaman no. 1 (AB1) went to collect the requested samples. They took samples from holds no. 1 and no. 2, but not hold 3 as it contained the same cargo as hold no. 1. At this point, the Third Officer went to place the samples at the accommodation ladder.  

Upon learning that one of the stevedores was selling phone cards, the Third Officer went to the ship’s office. When he returned, he could not find the Chief Mate or Able-Bodied Seaman no. 1 (AB1). Feeling suspicious, he then looked inside the hold no. 4 booby hatch and found both lying unconscious below. He then went back to raise the alarm and seek help.  

While the crew were preparing for the rescue operation with both the Third Officer and Chief Engineer in attendance, the Master rushed to the site. Despite advice not to enter the hold, he entered the tank and he too fell unconscious. This incident resulted in all three as fatalities.  


What went wrong? 

RightShip review of these and other enclosed space related fatalities, has identified the following direct and indirect factors were commonly present: 


Poor procedures - Inadequate/inappropriate entry into enclosed space SMS procedures, lack of familiarisation with the existing procedures, lack of training. 


Incomplete risk assessment - Failure to evaluate/understand/communicate risks associated with certain types of cargoes,  lack of understanding/appreciation to the risks associated with fumigation 


Incorrect atmosphere testing - Gases and vapors that are higher in density than air (such as H2S) sink to the bottom resulting  in a higher gas concentration closer to the tank top. Whereas, lighter gases, rise up and result in a higher concentration at the top area of the tank. Gases and vapors also tend to have higher concentration in areas where ventilation is least effective such as corners, and under inspection way/platforms. In one particular case, the investigation revealed that large and dangerous concentrations of H2S can in specific circumstances be present within tank residues and only manifest themselves when the top "skin" of the residue has been disturbed for example by person stepping into the residues.  


Human Factors - Improper decision-making, absence of proper safety culture over-reliance on false sense of safety (ie ‘we have always done it this way with no problems’), cultural differences/considerations wherein lower ranks are unable to challenge wrong decisions made by senior officers, crew behavior when commercial pressure is exercised.  


Furthermore, our analysis has shown in certain cases, commercial pressure was reportedly felt by crew to complete hold/tank cleaning in a time window that otherwise would not be considered adequate. As a result, crew members knowingly deviated from entry into enclosed spaces requirements and best practices to complete the task on time and meet the deadlines.  


What do good managers do? 

Our analysis has identified that proactive risk management steps consistently demonstrated can prevent these tragic incidents. These include adherence to regulatory and industry requirements below, and proper consideration human factors. 

  • SOLAS Chapter III Regulation 19.3.6 (Emergency Drills Training Requirement). 

  • SOLAS Chapter XI 1, Regulation 7 (Atmosphere Testing Instrument for Enclosed Spaces). 

  • MSC.1/Circ.1401 (Guidelines on Tank Entry for Tankers Using Nitrogen as an Inerting Medium). 

  • IMO Resolution A.1050(27), A guide to Bulk Carrier Operations (NI Publication). 

  • IMO MSC. 1/ Circ.1477 ‘Guidelines to facilitate the selection of portable atmosphere testing instruments for enclosed spaces,’ as required by SOLAS’ and 

  • ISGOTT Chapter 10 guidelines.  

  • ISM requirements.  


In addition, good managers have consistently implemented the following:  


  1. Behavioral safety and ‘Stop work authority’ 

Behavioral safety creates an atmosphere of safety partnership between vessel’s crew and shore-based management, "which focuses everyone’s attention on not only their actions, but others’ actions as well". This process empowers everyone to exercise ‘Stop work authority’ to prevent their fellow crewmates from getting hurt. This is particularly important to foster onboard amongst junior crew members who may fear retaliation if they raise a safety matter or challenge a senior officer (1).

  1. Safety culture approach 

Good managers invest in their crew to embrace safety as a lifestyle, rather than just another checklist with tickboxes.  

  1. Master’s overriding authority under International Safety Management (ISM) Code 

The ISM code gives the master the ability to exercise his/her overriding authority without fearing from management company’s retaliation. Good managers support and educate their masters around the proper use of the overriding authority, where others do not. Good managers Support their masters when they exercise their authority in the face of increased commercial pressure. 

  1. Know your vessel campaigns   

To prevent risks associated with entry into enclosed spaces, some managers have launched topic/risk specific safety campaigns. Such targeted campaigns aim to periodically evaluate all spaces on board and to identify, mark, and validate the enclosed spaces list to ensure its continuity and validity. 

  1. Single entry work permit 

No entry into enclosed space is valid for more than one access (even if it is the same work space). The entry permit must be limited by time. Should the crew require a break, a new permit (including all the checks and balances) must be issued.  

  1. Single purpose/space permit 

No entry permit is given to serve more than one space at the same time. 

  1. Single access at a time 

No more than one space entry at the same time. Some exceptions could be made provided that there are enough resources. 

  1. Resources and controls 

Evaluation of the available resources should be a continuous process that is carried out by onboard management. This includes: 

  • Sufficient trained personnel (Stand by, assisting and rescue) 

  • Sufficient equipment (PPE, SCBA, evacuation tools/equipment, lighting, ventilation, communication equipment suitable for the risks associated with the particular space, gas detectors, and atmosphere measurement equipment, etc.) 

  • Application of proper controls will ensure that there are no surprises in a work space. Such controls may include: 

  • Understanding the inherent risks. For example, for a cargo hold/tank, understanding the inherent risks associated with the type of current cargo (or previous in case it is empty). Whereas, for a closed store that is adjacent to a cargo hold under fumigation, then understanding the risks associated with the used fumigant become paramount.  

  • Proper ventilation throughout occupancy 

  • Atmosphere checks prior to entry and repetitive checks (that corresponds to a pre-established/agreed and recorded time line) throughout the occupancy. Such atmosphere checks should be done on different tank/hold levels. The sampling hose shold be lowered to as close as possible (but not touching) the tank bottom. Hose proper length should be marked by utilizing colored tape or such.Special training should also be given to the crew (as per manufacturers instructions) on the use of the aspirator bulb in the case of a manual pump or how long to run the indicators that are provided with powered fans to draw the required air sample. Testing should continue until readings are consistent.  

  • Proper attention is to be given especially when residues were/are left in the tank for an extended period of time. Especially if/when such residues are covered with a top film ‘skin’  layer which could release toxic gases when disturbed.  

  • Establishing proper communication with the authorized officer, standby personnel, and the bridge team. 

  • Carrying out a complete Task Risk Assessment which should be discused during a tool box meeting prior to entry (not solely depending on a pre-populated version of a generic risk assessment that is included in the risk register). 

  • Assigning an authorized, responsible officers and a team leader. 

  • Entry area to be surrounded with caution tape or markings that are clearly visible when it is not occupied and/or manned. 


  1. Prior planning and office authorisation 

Some managers have implemented the following: 

  • No entry into enclosed space permitted unless absolutely necessary and when they are, entry into enclosed spaces risk assessments (as minimum) must be reviewed and pre-approved by the office. 

  • Planned maintenance or otherwise required semi-routine jobs are to be pre-planned, discussed with the office, and all controls to be discussed before carrying out the job. All conditions ( including environmental) must be pre-assessed and taken into consideration. 


Where to find further information 

Dry Bulk vessels and managers can find additional  guidance material within our inspections standard RightShip Inspection Ship Questionnaire, under the questions 4.5, 4.6, 4.9, 4.16, 7.5 and 8.35. 



(1) Dominic Cooper, PhD (Behavioral Safety: A Framework for Success)