An accident waiting to happen
The Petrotrin oil spill
On a fateful December day when Christmas shopping occupied the minds of most people, a 16-inch diameter sea line broke at the State-owned Petrotrin refinery, sending a rush of black fuel oil into the Gulf of Paria and along the south-western coastline. The effect of that spill is still being felt today by fisher folk and people in poor coastal communities. The Express takes a close look at the chain of events that led to this country’s worst environmental disaster.
This is the second in a series of articles by Camini Marajh, head, Express Investigative Desk:
Sea line No 10, the 40-plus-year-old fuel oil line that ruptured on an early December morning, was an accident waiting to happen.
In addition to the severe external corrosion problems already identified, No 10 had five inoperable and leaking expansion joints, one missing in action altogether, leaking valves and flanges, segments of bare metal exposed, severely worn and loose safety wrappings, severely corroded chain and channel supports, cracks on support bolts and 41 identified areas where the channel beam support, including bearing plates and pile caps, were found to be severely corroded and perforated.
Inspection Advice Ticket (IAT) 763/2013 which was issued on December 27, 11 days after the rupture on No. 10, found a range of safety hazards, including cracks on bolting hardware associated with the expansion joints, leaking gaskets and metal loss of between two to three millimeters.
The inspection ticket laid bare some of the more vulnerable parts of Petrotrin’s most famous sea line, which successive management and boards of directors at Petrotrin ignored, allowing No 10 to continue its business of transporting hazardous product as usual, that is, until December 17, when the line finally gave way.
Petrotrin’s own reports reveal that the company intentionally and knowingly failed to comply with industry safety standards. And as reported yesterday, its lead investigator on the December 17 incident, Mervyn Cummings, found that the refinery failed to follow its own mechanical integrity management plan.
The architect of the plan, Gamini Hapuarachchi, Petrotrin’s former head of Inspection Engineering, was clear that the ten-year inspection programme, if followed, would keep the refinery’s marine infrastructure safe.
The Hapuarachchi Plan
He put it this way in his report: “The ten-year sea line inspection programme was generated utilising the mechanical integrity report. This programme displays the inspection schedule for each sea line based on its risk ranking, location and service and inspection frequency.”
Noting that the sea lines were exposed to a marine environment, Hapuarachchi said: “The corrosiveness of each line varies with the degree of exposure. Subsea lines are classified into two sections, above water as well as riser piping. Special care needs to be addressed to riser piping in the splash zone areas.
“These lines are exposed to a high degree of turbulence, thereby making them susceptible to an increased rate of erosion corrosion. These riser piping are rated as high risk lines and are assigned inspection intervals of two years. Recommendations are made to apply the required coatings or wrappings on these lines so as to maintain their integrity.
“The environmental impact played an important factor in the risk ranking of the lines due to the consequences of an oil spill and its effect on the environment and sea life. Samples were taken from failed sections of sea lines in various services. On inspections of these failed samples it was noted that the failure of the lines were primarily due to external corrosion. Internal corrosion of these lines were found to be negligible when compared to that of the external.”
The 2010 Hapuarachchi plan said: “A risk assessment was carried out on each sea line where each line was ranked based on their probability and consequence of failure. The risk assigned to each line is based on the Risk Assessment Matrix implemented within Petrotrin. This classification is done for high, medium and low ratings for the sea lines, where high risk requires a two-year inspection frequency and medium and low requires a four to six and a six to ten-year frequency, respectively.”
“A major factor that was taken into consideration in the determination of the
consequences of failure is that of the availability of spare lines. Much emphasis is paid on the effect of assets and environment, if a failure should occur. It is assumed that the mode of failure of these lines being that of a corrosion hole.”
The only trouble with the Hapuarachchi plan is Petrotrin’s failure to implement.
—To be continued on Sunday