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 approximatel
