Following the bulk carrier MV Cheshire (IMO 9593646) disaster in August 2017 the Isle of Man Registry has recommended that the IMO and marine industry consider the introduction of mandatory thermo-graphic determination to ensure that hot spots do not exist in cargo hold boundaries prior to loading any Ammonium Nitrate Based Fertiliser (ANBF) cargo.
The report also said that “a quick efficient response by a well-informed, well-equipped and well-trained crew may have saved the vessel from being lost” and suggested that the “non-hazardous” classification for ANBFs be changed to “not otherwise classified”.
The vessel was loaded with a full cargo of “non-hazardous”-class ANBF fertiliser and was travelling from Norway to Thailand to discharge, but experienced elevated temperatures in cargo holds 4 and 5 (CH#4, CH#5) on August 12th. ANBF is currently categorized into three groups, two of which are determined to be “hazardous” (UN 2067 and UN 2071); the third is classified ANBF “non-hazardous” (and has no UN number assigned).
When opening CH#4 hatch cover drains for daily atmospheric checks, small collections of water and a barely discernible “light dust” were observed. This continued to deteriorate and a foul smell was subsequently detected.
The cargo manufacturers were contacted for advice. They advised that a cargo thermal decomposition was most likely occurring and the Master was instructed to open the cargo hold openings, and if possible the main hatches, to achieve maximum ventilation/gas dispersion purposes.
The manufacturers advised that the best way to stop the decomposition was to cool the area with water directly by means of a Victor lance and gave the vessel instructions how to make these. The report observed that there was currently no requirement for their provision and the vessel had no such equipment on board, but they constructed some from materials to hand.
With rising temperatures and increasing quantities of toxic gas by August 12th, and despite attempts at cooling the decomposition front with water, the situation was clearly worsening. The manufacturer dispatched a cargo surveyor to render expert assistance on board the vessel to deal with what was now a confirmed cargo thermal decomposition.
At 00.40 on August 14th there was a “dull explosion”, following which there was a sound “like heavy rain” on the bridge. During a brief spell of limited visibility and under the vessel’s deck lighting, it became obvious that the CH#4 hatch cover had been forced open and fertiliser was seen all over the deck. The toxic gas colour had also changed from white to orange, indicating a more advanced stage of decomposition.
On August 14th the Master commenced permanently going slowly astern to try and keep the vessel clear of the gas cloud, but the vessel’s handling characteristics at this speed meant the bows kept turning to starboard and the accommodation, bridge and engine-room continued to be suffused with toxic gas.
The Master informed the owner of his decision to send a distress signal to Spain Maritime Rescue Co-ordination Centre (SMRCC) to evacuate the crew from the vessel, whilst it was still capable of being positioned to provide a degree of egress safety. Spain MRCC responded with two SAR helicopters and successfully landed the crew and cargo surveyor in Las Palmas.
The Spanish authorities now believed that sufficient steps had been taken and, having had previous experience of ANBF decompositions (M/V Ostedijk off the coast of Galicia), knowledge of the health hazards they could present and the difficulties of arresting a decomposition, the Gran Canarias port authorities refused the vessel entry to port limits, instructing them instead to hold position approximately 15nm South of Gran Canarias until the decomposition was confirmed as extinguished and the prospect could be reviewed once more.
The vessel had arrived at a safe position 45 miles south of Gran Canaria on the afternoon of August 13th. The cargo manufacturer sent four representatives to Las Palmas to advise on cargo cooling.
Resolve Marine was appointed to attend the vessel and deal with the cargo problem and arrived in Las Palmas on August 14th.
A standby tug from Sasemar stayed with the vessel and an access ladder was rigged. Resolve Marine was on station alongside the vessel from August 16th but had failed to get on board due to adverse weather conditions, the heat and the fumes being generated from the affected holds.
The vessel, being no longer under command or power, drifted (under MRCC supervision) in a SouthWesterly direction further away from land whilst the decomposition continued.
The cargo manufacturers advised that there was a possibility of further deflagrations or explosions and, in the first few days, safe access to Cheshire was impossible.
Salvors stood by the vessel and continuously tried to secure a tow line. Prevailing weather and decomposition conditions meant that this could not safely be achieved until 15.00 on August 21st, by which time the decomposition reaction had also significantly run its course and subsided.
Although damaged in its entirety by the decomposition, approximately 23,183 tons (54%) of the cargo was consumed by the reaction and by toxic decomposition products being released to the atmosphere. Only 19,471 tons (46%) remained on board after the event.
Cheshire was successfully boarded by Salvage teams for initial damage assessment and tow line connection and although the trim of the vessel had changed due to loss of cargo from all five cargo holds (due to the reaction process), the vessel was still determined stable enough to be towed under good weather conditions to a port with suitable handling facilities for the decomposed cargo.
Manufacturers advised Puerto de Motril was one such location and this is where the vessel was eventually to be towed for discharge and damage assessment. Under LOF – SCOPIC the tow continued to Puerto de Motril. At one point the tow line parted due to lack of lubrication at contact points with the hull but this was rectified very quickly and the vessel was eventually secured alongside at 19.30 on September 13th.
Following chemist assessment to determine and certify it was safe to gain access, Owners, underwriters and the vessel’s Class Society surveyors, managers and local authorities were finally able to get their first close-up inspection of Cheshire.
It became clear that significant structural deformation had occurred in addition to the visibly obvious structural damage, and on December 4th 2017, under the vessel’s hull and machinery policy, the underwriters declared the vessel a Constructive Total Loss (CTL).
Because these discharged cargo maximum temperature requirements were stipulated for environmental and personnel safety, despite repairing and using the vessel’s own cranes to move hot cargo to cooler cargo holds (to assist cooling down to 500 C), the vessel was not completely unloaded until 7th December, four months and one week following the initial decomposition event.
The IoM investigation observed that, despite being recognized by the fertiliser industry as the most effective means to cool decomposition, Victor lances were not standard items of equipment required to be carried by either SOLAS or the cargo charter party. Thermal imaging devices, which are valuable to assist in identifying the hottest location, are also optional. (In this case the vessel had one and it was used to correctly identify the hot spot to be in CH#4 adjacent to the Australian ladder (a steel combination vertical/spiral hold access ladder fitted with a steel protection boundary and lighting for safety)).
The investigation found that “a quick efficient response by a well-informed, well-equipped and well-trained crew may have saved the vessel from being lost”.
Determination of the actual initial cause of the decomposition was still being attempted by interested parties from the evidence collected. The vessel has since been towed for recycling at a certified facility.
The investigation also recommended:
· that operators of vessels certified for, and intending to carry, ANBF at any time develop Safety Management Systems to include ANBF-specific guidance, including which measurements should be recorded and trended. The provision of any specialist equipment would require crew training and information as to its proper use.
· For sea transportation, it was recommended that fertiliser manufacturers include specific emergency information related to cargo decomposition symptoms and suppression within their Material Safety Data Sheets for each grade manufactured, highlighting the unique dangers decomposition presents and urging early contact.
· that IMO populate IMSBC sections for all grades of ANBF with consistent information, what signs to look for, how to respond and what type of specialist safety equipment should be provided for use in a decomposition event
· that IMO consider changing the BCSN from “Ammonium Nitrate Based Fertiliser (non-hazardous)” to “Ammonium Nitrate Based Fertiliser (not otherwise classified)”
· IMO consider providing additional guidance specifically in connection with ANBF cargo decomposition by means of an MSC circular.
· that Operators of vessels carrying ANBF cargoes consider the carriage of additional equipment (Victor Lances, additional SCBA, thermal detection etc.) in order that ship staff can be in a better position to respond quickly and effectively to a decomposition event.
· that the IMO consider the merit of introducing a requirement to monitor cargo hold oxygen content as an added safeguard.
· that IMO and industry experts re-consider whether the S.1 test is truly representative of the bulk mode of transportation.
· that fertiliser manufacturers advise how containment affects the decomposition process and if carriage of more than one grade together may produce unexpected results.
· that fertiliser manufacturers determine how Matrix formation can be prevented and promulgate the results to industry.
Vessel owners – Bibby Transport Ltd, Liverpool, UK.
Vessel managers – V.Ships Asia Group Pte Ltd, Singapore.
Cargo charterers – J. Lauritzen Singapore.
Cargo manufacturers – YARA Porsgruun, Norway.
Salvors – RESOLVE Salvage & Fire (Europe) Ltd. Of London, UK
Amlin Syndicate 2001 was claims leader for Hull and Hull & Machinery, on behalf of Bibby Ship Management. Gard had a subscription interest