A report by In-Corr-Tech Ltd, the company hired by the Occupational Safety and Health Agency to investigate the accident at Paria Fuel Trading Company (Paria) Ltd berth No 6, says both Paria and Land and Marine Construction Services Ltd (LMCS) Ltd failed to recognise the potential for a latent hazardous differential pressure condition being created by the method used to carry out the operation.
The company said there was a lack of thoroughness of the bid evaluation process on Paria's part.
In-Corr-Tech reviewed documents and information OSHA presented to it , including Paria’s scope of works (SOW), LMCS’s method statements, job-safety analysis and risk assessment, and relevant work permits, risk analysis, dive plan and schedule.
It inspected the associated equipment used, including compressors, hoses, filter pots, the inflatable pipe plug, the mechanical seal, scuba equipment, and the crane used in the exercise.
It also constructed a scale model to recreate the February 25 incident. It was not able to inspect the hyperbaric chamber, as it remained underwater.
The executive summary of the report said, “The root cause of this accident was the failure by both the client, Paria, and the contractor, LMCS, to recognise that a latent hazardous differential pressure condition, Delta P, would have been created by the methodology used in the execution of the works, with particular reference to the removal of fuel oil from Sea Line SL36. If this Delta P hazard was recognised, then simple mitigation steps and/or change in methodology could have been instituted to eliminate this hazard.”
It said the initial method statement LMCS supplied for installing the flange on the riser was based on removing oil from the line using an air-driven pump, but this procedure was changed to air-blowing, and this change was not addressed in subsequent job safety analyses (JSA) or method statements. It said neither Paria nor LCMS gave a reason for the change.
“Paria’s maintenance department, as recorded by OSHA, stated that line contents were indeed removed by air blowing from No 5 Berth to No 6 Berth. This technique, although not stated in LMCS method statement or in Paria’s SOW, would have definitely removed way in excess of the optimum quantity of oil from the line, thus creating a significant continuous gaseous void between Berth No 5 and Berth No 6 together with empty risers. This condition would have introduced a very dangerous latent differential pressure condition as soon as the inflatable plug and mechanical seal were installed in the line and the habitat placed and pressurised.”
It said the LMCS method statement said the procedure for removing line content between the two berths said “(a) Using air driven pump, pump out approximately 300 barrels of line content, and (b) “Once level in the riser dropped to 35 feet below sea level, a line plug will be installed.”
The report said “(a) and (b) are contradictory, as removal of line contents to 35 feet below sea level in the riser would have been equivalent to approximately 30 barrels of oil removal, with no gaseous void formation on installation of the mechanical seal and inflatable plug. On the other hand, as stated by LMCS: '(a) Pumping out 300 barrels with an air pump does not equate to dropping level in riser to 35 feet below sea level.' This discrepancy was not addressed in Paria’s bid evaluation. Further, LMCS project schedule calls for draining of line from day one of job execution, further adding conjecture to this exercise.”
The report said both Paria and LMCS overlooked the creation of the potential for this Delta P hazard.
“LMCS JSA, Paria’s permit to work, LMCS method statement, LMCS risk assessment, LMCS tool box meeting, LMCS dive plan and Paria’s bid evaluation of LMCS proposal all failed to identify this potential Delta P hazard and hence no steps to eliminate the hazard were implemented. This latent hazard existed at the onset of work within the habitat and became active when the divers were attempting to remove the primary seal (inflatable plug) from within the riser.”
In-Corr-Tech noted that during the toolbox meeting on February 25, at which all four of the divers who died and the surviving diver were present, the topics discussed were covid19 protocols, communications, choppy waters, weather, slips and awareness.
“No discussions on the actual work activities planned for the 25/02/2022, the day on which the accident occurred, were recorded. No discussions were held on one of the key activities eg removal of the mechanical seal or removal of the inflatable plug.”
It said appropriate JSAs and risk assessments were not seen for several key activities in the LMCS proposal supplied to OSHA from Paria with respect to safety issues.
It said Paria’s scope of works said the bidder was to supply a detailed method statement identifying elements of the project including safety considerations, lift plan, dive plan, quality assurance, safety analysis and a JSA which showed the contractor's procedures for “removal of hydrocarbon from line with zero spills.”
“This was not seen in the contractor’s submission and was considered to be a grave oversight in the bid evaluation as it had direct bearing on the accident. This reflected the lack of thoroughness of the bid evaluation by Paria. LMCS Method Statement #116, items 56 and 57, pertaining to the removal of migration barrier and inflatable plug, could have only been applied safely if a Delta P condition was not present. This was also a grave oversight by both Paria and LMCS during this evaluation and subsequent discussions with LMCS.”
It noted that the JSA dated December 10, 2021, did not address key activities in the associated method statement, dated January 4, 2022, such as line content removal, removal and installation of plugs. It said the dates suggest an anomaly, as the method statement usually precedes the development of the JSA, and the JSA should have been rewritten to reflect the requirements of the method statement.
“This work permit focused on too many key activities, and almost covered the majority of works in Section ‘A’ of Paria’s scope of works. Consequently, appropriate, relevant and detailed JSA/risk assessment for key activities were not produced. The said work permit covered six key activities and was accompanied by one JSA that was too generic and not specific to this high-risk job.”
It noted that supply air from the compressor into the habitat speeded up the vortex formation and strengthened its force and suction.
“On his return up the riser, the lone survivor stated that he was approximately five feet from the top of the riser and within the habitat, confirming that the compressor was in operation and supplying air to the habitat. This confirms that when the flow into the riser was stabilised, air supplied by the compressor forced the water back down in the habitat, again creating a 'dry' workable environment.”
In-Corr-Tech said the crane, compressors, hoses, air filter pots, scuba gear, inflatable plug, supply air problems, and the hyperbaric chamber were not thought to have contributed to the incident.