After a string of recent cases of protesters meddling with pipelines, there is concern whether the tampering could escalate into more serious action.

There were four incidents on Enbridge's Line 9 between November and January, including sabotage to the pipe near Cambridge, Ont., and a tampered valve near Hamilton.

'It's seen as a socially acceptable way of protesting and it's not' - Chris Bloomer, CEPA

Pipelines are a target, but they shouldn't be, according to the chief executive of the Canadian Energy Pipeline Association.

"You have people going into these things, tampering with them, trying to close the valve, getting inside the fence, and creating a very big potential environmental risk and safety risk to them," said Chris Bloomer.

Concerns about people taking extreme action have been raised recently as the debate over pipelines escalates and the rhetoric ramps up. Calgary's former police chief warned some of those inflammatory words raise the risk someone could blow up pipelines.

The incident in Hamilton was described in a post on Earth First Newswire, an environmental activist website.

"Our hearts were bursting with love and cheer after hearing of the many times our friends have courageously shut down pipelines in recent months," it said.

Up to 300,000 barrels of oil a day flow from Alberta's oilsands to Montreal's refineries using the Line 9 pipeline after it was recently reversed. Vandalism has led to oil spills in the past, including in northwestern Alberta in 2011.

"It's seen as a socially acceptable way of protesting and it's not," said Bloomer. "It's harmful, it's highly risky and it can create potential issues with people getting hurt or an environmental spill." 

Bape protest

A protester unfurls a banner during a Quebec environmental hearings on TransCanada's Energy East pipeline proposal Monday night. (CBC)

Bloomer said it's fine to criticize pipelines, but it's too risky to physically tamper with them. He wonders why there wasn't more political pushback after the vandalism occurred.

"That's almost seen as an accessible form of protest and public disobedience. If someone did that on a runway at Pearson [International Airport in Toronto] that would last a nanosecond. If somebody went into a big substation, power station or dam and did something like that, that would not be accepted. So why is that accepted for pipelines? We need to have some education around that," he said.

Enbridge said tampering with equipment or entering locked areas is hazardous behaviour to the public and environment at large. The company is assessing and employing various additional, permanent measures to enhance security and safety to help prevent similar activities in the future, he said.