Fact of fatal accident not proof of safety violation in absence of clear evidence of how it happened
An Alberta court has overturned the conviction of a well-drilling company on two charges stemming from the death of a worker at a drilling site and ordered a new trial.
Frazier Peterson was a floorhand for Precision Drilling, a drilling rig contractor based in Calgary. Peterson was working on a rig drilling an oil well near Grande Prairie, Alta., on Dec. 12, 2010. The rig being used had a rotary table mechanism with a drill bit on the end and was drilling angled wellbores — or holes — rather than a straight vertical direction. In this case, the rig was drilling a hole in an “S” formation.
The rig’s crew was removing the drill pipe from the S-shaped hole two 9.3-metre lengths at a time — a procedure called “tripping out.” The total depth of the hole was 2,416 metres. The rig manager, consultant, driller, derickhand, motorman, and two floorhands including Peterson were present.
As a length of pipe came up, it released torque that caused it to strike Peterson. None of the other workers witnessed the drillpipe come into contact with Peterson, but they discovered him injured shortly thereafter. Peterson’s hard hat wasn’t damaged, but it became evident that he suffered blunt cranial trauma, killing him.
An occupational health and safety inspector came to the wellsite following the fatal accident and issued a stop-work order on that particular rig. The stop-work order was lifted the next day.
Occupational health investigators learned that the tripping out procedure had been done 11 times that day using the same procedure without incident before Peterson was killed. They also discovered that another drilling company called Savannah had a device on one of its rigs designed to help divert trapped table torque, though the rig wasn’t the same type as the one that killed Peterson. Savannah’s device also wasn’t mandated by any regulation or industry standard.
Precision Drilling developed an interlock device for all its rigs a few days later, though it still wasn’t made mandatory by government regulations or industry standards.
Company developed interlock device
An expert determined that the table torque — built up while the drill table was turning the pipe and the drill bit created resistance on the bottom — was trapped because the brake was engaged. As a result, Precision Drilling was charged with failing to ensure the health and safety of its employees under the Alberta Occupational Health and Safety Act and failing to eliminate or control a hazard to workers, as required under the province’s Occupational Health and Safety Code 2009.
The trial judge found that the fact Precision Drilling made modifications to its drill rigs after the accident, as well as the fact a competitor, Savannah, had adopted an interlock device, was proof the company should have done more to prevent it. The judge also found the accident was caused by torque building up from the brake being on and the driller attempting to lift the drill stem while the floorhands reached in to remove slips — the injury to Peterson’s head was consistent with the position of reaching for the slips. As a result, the company was convicted of both offences and fined a total of $400,000.
Precision Drilling appealed the convictions to the Alberta Court of Queen’s Bench. It argued it met all industry standards and legislative requirements and it couldn’t have been expected to have devices in place that were recently developed and not mandated for use. In addition, the company had a good safety record and took safety seriously — the rig manager even had a discussion with Peterson about trapped torque before the accident.
The court found that there was no clear cause for Peterson’s fatal injuries, because no-one witnessed them and no-one could say for sure what exactly caused them — only theories.
The court also found that the interlock device used by Precision’s competitor and the devices the company developed after the accident were designed to specifically stop trapped table torque from building up and being released unexpectedly, but there were other types of torque that could develop as well. There was no evidence trapped table torque actually caused the injury, said the court.
“In any event, using the essence of the Crown’s expert witness’ opinion about torque, anyone would understand that resistance while drilling could be caused, not only by the bit on the bottom, but by contact with the wellbore, especially when the wellbore was in a lazy S formation,” said the court. “In addition to contact with the wellbore, there was evidence that torque could be created in other ways; for example, the rig manager indicated that a mud motor can cause torque.”
The court determined that the trial judge erred in finding that Precision Drilling had not proven that it had done everything reasonably practicable to avoid Peterson’s death, since the evidence didn’t support a specific cause. Without that specific cause, it couldn’t be determined that the company didn’t do everything it could. In fact, since the cause of the accident was so difficult to determine, the company couldn’t be expected to know what it could have done to avoid it, said the court.
The court also noted that the government allowed Precision Drilling to keep drilling and tripping out without an interlock device after a one-day stoppage of work, indicating there were no concerns the company wasn’t following safety standards and the use of interlock devices wasn’t required. In addition, the procedure of floorhands entering the rotary table area to remove slips didn’t change, even though that’s what Peterson was doing when he was killed.
The court overturned the conviction of Precision Drilling on both charges, finding the trial judge misinterpreted the evidence. A new trial on the charges was ordered.
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