TT Talk - The oxygen we breathe requires clear thinking
On Monday, 26 May 2014 three crewmen on board a general cargo ship were killed after entering the ship’s hold. The ship was carrying a seemingly harmless cargo of sawn timber. During the passage the oxygen in the hold had been significantly depleted. This is a stark reminder of the need for thorough risk assessment, vigilance and, arguably, personal oxygen meters.
In November 1997, the IMO adopted Resolution A.864(20) regarding entry into enclosed spaces aboard ships. The recommendations encouraged the adoption of safety procedures aimed at preventing casualties to ships’ personnel entering enclosed spaces where there may be an oxygen deficient, flammable and/or toxic atmosphere.
A report produced by the Marine Accident Investigators International Forum (MAIIF) in 2009 identified 101 enclosed space incidents resulting in 93 deaths and 96 injuries since the resolution had been published. As a result, amendments were made and a new resolution [Resolution A.1050(27)] was published by the IMO in 2011, specifically relating to safety management for entry into enclosed spaces, requiring companies to elaborate their schemes to ensure that training is provided for the use of atmospheric testing equipment in such spaces and a schedule of regular on-board drills for crews.
‘Enclosed spaces’, as used by the IMO, refers to a space that has any of the following characteristics:
1 limited openings for entry and exit;
2 inadequate ventilation; and
3 is not designed for continuous worker occupancy
Some refer to ‘confined spaces’, such as the US Government, replacing ‘inadequate ventilation’ with ‘is large enough and so configured that an employee can bodily enter and perform assigned work’.
In view of accident reports, the dangers associated with entering confined or enclosed spaces persist; here is a summary of initiatives underway to reduce the risk.
The forthcoming IMO/ILO/UNECE Code of Practice for packing cargo transport units (CTU Code) includes clear instructions about entering a closed CTU. The doors should be opened for a period of time – enough to allow the internal atmosphere to regularise with the ambient. During this time more checks should be made for signs, marks or other labels that may indicate that those involved in unpacking the CTU could be at risk because of the nature of the cargo, including fumigation.
“Surveys carried out in Europe from 2007 until 2012 found a number of undeclared gases carried in CTUs”
Surveys carried out in Europe from 2007 until 2012 found a number of undeclared gases carried in CTUs. Many such gases are bi-products of manufacturing processes and constitute a severe risk to those involved in unloading. Where there is concern about the cargo carried, containers should be checked for possible toxic gases against the nationally set threshold limit value (TLV) of the relevant chemical. Reliance on the sense of smell is flawed; most of these gases will be well above their TLV by the time they can be detected. However, taking air samples is also fraught – not least, requiring a device that identifies the gas, before the concentration of the gas can be measured.
Atmosphere testing instruments
Since its resolution in 2011, the IMO has agreed to formulate amendments to the Safety of Life at Sea (SOLAS) Convention and relevant codes concerning mandatory carriage of appropriate atmosphere testing instruments on board ships.
There has been extensive discussion at the IMO. A significant majority supported draft amendments to SOLAS regulation XI-1/7 relating to the carriage requirements for instruments that test the atmosphere of enclosed spaces together with associated draft Guidelines. Detailed work is underway, not least dealing with the issue of training of seafarers. The scope of the amendments is limited to measuring oxygen, flammable and toxic gases (carbon monoxide and hydrogen sulphide) in enclosed spaces. These changes relate to enclosed spaces normally found on ships, and do not specifically cover containers and other such enclosed or confined spaces. Cargo related toxic bi-products have not been considered in these amendments but still place those involved in the unpacking of containers at risk.
The associated Guidelines refer to the instrument that is used to test the atmosphere in an enclosed space before entry and at appropriate intervals thereafter until all work is completed. They do not, however, refer to a personal gas detector, intended to be carried by an individual whilst inside the enclosed space. Thus, while this will reduce the risk to those entering into the space from which the atmosphere has been tested, it may provide a false sense of protection as atmospheric conditions may vary across the enclosed space that could place operators at risk when remote from the sampled area.
Best practice – such as adopted by repair organisations associated with the International Tank Container Owners (ITCO) – requires those entering a container (eg. inspectors and/or repairers) to carry personal detectors that will confirm the presence of sufficient oxygen. Recent reports by the US Coast Guard identify examples where their surveyors, wearing oxygen detectors, were alerted to low oxygen levels as they prepared to enter enclosed/confined spaces; for the price of a couple of hundred dollars lives had been saved.
Pithy guidance has been provided through the joint ICHCA/TT Club safety cards on entry into enclosed spaces But it must be remembered that people will continue to enter containers and other enclosed/confined spaces with disastrous consequences, and others will rush to their assistance. Unplanned rescue, such as when someone instinctively rushes in to help a co-worker, can easily result in a double fatality or even multiple fatalities if there is more than one would-be rescuer. Over 50% of the workers in enclosed/confined spaces die while attempting to rescue other workers. An unplanned rescue could be the last!
“Over 50% of the workers in enclosed/confined spaces die while attempting to rescue other workers”
We hope that you have found the above interesting. If you would like further information, or have any comments, please email us, or take this opportunity to forward to any colleagues who you may feel would be interested.
We look forward to hearing from you.
Risk Management Director, TT Club