Hamilton police said protesters were given 24-hours notice to leave after Enbridge obtained a court injunction Tuesday, and 18 protesters were arrested when they refused to leave the station.
Police spokeswoman Debbie McGreal-Dinning said 13 men and women, between 19 and 25-years-old, were charged with trespassing. Four protesters were charged with mischief and one other with breaking and entering with intent to commit mischief.
She said all were being released after they were processed.
"At this point almost everyone has been released," said protester Sarah Scanlon, who wasn't arrested. "Spirits are extremely high."
Scanlon, 27, said police were "heavy-handed," arresting protesters who were standing on public property.
McGreal-Dinning said she couldn't comment but said the arrests occurred without incident.
Protesters had formed a blockade at the Line 9 pumping station in North Westover, about 30 kilometres northwest of Hamilton, on June 20. They oppose Enbridge's plan to reverse the flow of oil in a stretch of pipeline from Sarnia, Ont., to Montreal to bring in oil from Alberta instead of relying on imports.
The protest group, dubbed Swamp Line 9, said it fears the move could lead to a possible breach in the pipeline because it would be carrying diluted bitumen from Alberta's oil sands, which is heavier than light oil.
The protest action is also part of the Idle No More movement. The group said the pipeline runs through First Nations territory and Enbridge didn't consult with the community.
Enbridge spokesman Graham White said the concern over a breach is unwarranted, as the oil in Line 9 is a processed grade of crude.
"The vast majority of the product to be shipped in reversal will continue to be light oil," he said. "Line 9 has an excellent track record. We've operated as a safe line for the nearly 40 years it's been in the ground."
White said conversations with the protesters had been unproductive during the week, prompting the company to obtain the court injunction.
Line 9 runs in two sections from Sarnia, Ont., to North Westover, and then from there to Montreal. Enbridge has already received approval from the National Energy Board to reverse oil flow in the Sarnia-North Westover section of the pipeline and is waiting for approval on the Montreal section.
White said Enbridge also plans to increase the pipeline's capacity from 240,000 barrels per day to 300,000. The pipeline's diameter will not be expanded but instead a chemical will be put into Line 9 to reduce friction and allow more oil to pass through.
"What we say is that our Eastern refineries are on a diet of expensive foreign crude," he said, adding that Line 9 transports oil imported from Africa, South America or the Middle East. "It's an important economic decision to be able to have our Canadian refineries refine our Canadian crude."
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