麻豆传媒

The U.S. National Transportation Safety Board said a rupture and prolonged leak from an Enbridge pipeline in Michigan two years ago were caused by 鈥減ervasive organizational failures鈥� at the company, as well as weak oversight by the agency in charge of pipelines and hazardous materials.

The NTSB released its final report into the leak at a three-hour meeting Tuesday, during which officials slammed Enbridge鈥檚 handling of the leak and its failure to address a defect in the pipeline that was identified years before it ruptured.

According to the report, the 鈥減robable cause鈥� of the rupture was 鈥渃orrosion fatigue cracks that grew and coalesced,鈥� as well as cracking and corrosion in the pipe鈥檚 coating.

The rupture occurred on Line 6B around 6 p.m. on July 25, 2010, as Enbridge鈥檚 control centre, located in Edmonton, was undertaking a scheduled 10-hour shutdown of the pipeline.

Oil gushed from the ruptured pipeline for more than 17 hours before the leak was discovered. More than 3 million litres of crude spilled near Marshall, Mich., into the Kalamazoo River and Talmadge Creek.

Despite repeated alarms and warnings at the control centre of a potential problem on Line 6B, staff did not begin to respond until they were notified by a local employee of a gas utility of oil in the area.

The report laid partial blame for the rupture and prolonged spill on Enbridge鈥檚 鈥渄eficient integrity management procedures that allowed well-documented crack defects and corroded areas to propagate until the pipeline failed.鈥�

It also cited inadequate training of control-centre personnel, which allowed the spill to go undetected for so long, including through two re-starts of the pipeline. In addition, investigators noted that the company failed to educate the nearby community about the pipeline鈥檚 location, which resulted in the leak going undiscovered by local emergency responders despite receiving reports from local residents of an odour.

The report also laid some blame on the U.S. Department of Transportation鈥檚 Pipeline and Hazardous Materials Safety Administration (PHMSA). The report criticized the agency鈥檚 weak regulations for assessing cracks and ensuring that they get repaired, and decried its 鈥渋neffective oversight鈥� of pipeline integrity management systems and control-centre procedures.

The report also criticized both the company and PHMSA for poor emergency preparedness planning and oversight.

The report included 19 recommendations, six of which applied to Enbridge, including better training for control-centre staff, improved processes for identifying a leak and more thorough emergency response plans.

As the meeting got underway Tuesday, the chair of the NTSB slammed Enbridge over its handling of the leak.

Deborah Hersman said a defect in the pipeline that caused the rupture was identified in 2005, but nothing was done to address the risk.

According to tweets sent by the NTSB鈥檚 official Twitter account, Hersman told the meeting that Enbridge鈥檚 response was 鈥渋nadequate to a large-scale spill.鈥�

She said the Calgary-based company鈥檚 鈥減oor handling of (the) rupture reminds one of Keystone Kops.鈥�

A statement on the NTSB website said clean-up efforts continue, and have so far cost more than $767 million.

Enbridge CEO Pat Daniel issued a news release Tuesday, saying the Kalamazoo River reopened in June to recreational users. He also noted that wildlife is returning to the area.

"We believe that the experienced personnel involved in the decisions made at the time of the release were trying to do the right thing," he said.

"As with most such incidents, a series of unfortunate events and circumstances resulted in an outcome no one wanted."

Stephen Wuori, Enbridge鈥檚 president of liquids pipelines, said in the same statement that the company conducted a 鈥渄etailed internal investigation鈥� into the incident and has made 鈥渘umerous enhancements鈥� to its 鈥減rocesses, procedures and training,鈥� including at the control centre.

鈥淚ncident prevention, detection and response have also been enhanced,鈥� Wuori said. 鈥淲e will carefully examine the findings in the NTSB report to determine whether any further adjustments are appropriate."

Earlier this month, PHMSA issued its own report into the spill, and announced a proposed civil penalty to Enbridge of $3.7 million.

The agency listed 24 violations of hazardous liquid pipeline regulations, including a failure to repair corrosion problems at the leak site.

The agency also said Enbridge restarted the line twice despite multiple alarms at its control centre that indicated abnormal operating conditions. More than 2.5 million litres of oil was pumped into the pipeline after the rupture.

Enbridge was given 30 days to respond to the proposed penalty.

On Tuesday, Hersman criticized PHMSA, saying, "Delegating too much authority to the regulated to assess their own system risks and correct them is tantamount to the fox guarding the henhouse.鈥� But she also hailed the decision to recommend the fine as a 鈥渘ecessary and important step.鈥�

The two reports will likely give ammunition to opponents of Enbridge鈥檚 proposed Northern Gateway pipeline that would funnel oil from Alberta to B.C. for shipping to coveted Asian markets.

The price tag of the proposed pipeline is $5.5 billion.

Greenpeace representative Mike Hudema said the report should give regulators pause as they consider the project.

"This should be the last warning signal we need that Enbridge cannot be trusted to build a tar sands pipeline through the largest intact temperate rainforest left on the planet," Hudema told The Canadian Press.