04/12/2015 12:56 EDT | Updated 06/16/2015 09:59 EDT

Vancouver oil spill: Coast Guard defends cleanup response time

After widespread criticism of its oil cleanup response effort, the Canadian Coast Guard has issued a detailed timeline outlining the sequence of events immediately following the detection of a major oil spill in Vancouver's English Bay.

Coast Guard Commissioner Jody Thomas said, in a statement released Sunday, the agency was first notified by a recreational boater of a slick around the bulk grain carrier Marathassa at 5:10 p.m. PT Wednesday.

Within four minutesthe coast guard says it had notified its emergency management partners whose job is to inform local shore-side authorities including municipal governments and First Nations.

At 5:38 p.m. PT, the coast guard said a harbour vessel for the Port of Vancouver had assessed the spill as minor and unrecoverable, but the coast guard's own assessment, an hour later, determined the spill was more serious.

Thomas said the Western Canada Marine Response Corporation was tasked with the oil's cleanup and arrived on scene at 9:25 p.m. PT.

Contrary to criticism that nothing was done until the next day, Thomas said crews went to work that night.

"Our partners carried out skimming in the dark and completed securing a boom around the vessel by 5:53 a.m PT. Even before most British Columbians woke up, the boom was completely surrounding the suspect vessel," she said. 

"[Eighty] per cent of the spill was not only contained, but was recovered within 36 hours. The Canadian Coast Guard's response to the Marathassa spill was exceptional by international standards."

However, during a morning news conference, Assistant Coast Guard Commissioner Roger Girouard said that even though the Coast Guard sent out the proper notifications, there was a break-down in the communications chain.

"There were some human factors in a number of organizations where the relay of the intent of the alarm was not always received or passed on," he said. I can tell you that the coast guard as an organization passed the message on. I can also tell you that the alarm bell did not particularly make it to the mayor of Vancouver."

Girouard declined to specify where the communication breakdown occurred, but said all agencies are reviewing the chain of events to come up with a simpler, faster notification that would be more widely broadcast.

"We thought we had a sophisticated system in place. Something went awry," he said. "We will fix it."

Thomas said cleanup over the next several days will be focused on the shoreline. 

Now that the Marathassa is confirmed as the source of the pollution, she said the vessel's owners will be responsible for covering the costs of the operation.