The Department of Environment says it's too soon to say whether Irving Oil will face any charges in connection with a butane leak in east Saint John that resulted in a full emergency response and forced the evacuation of area homes and businesses.

It's also unclear what remedial action may be required, said Marc André Chiasson, the department's spokesperson.

"The situation is still with [Saint John] Hazmat/Fire and our inspectors have not been able to investigate at this time," Chiasson said in an email to CBC News on Tuesday afternoon.

The leak, discovered Monday morning at Irving's Saint John East Terminal on Bayside Drive, was stopped and contained by Tuesday morning. But officials still don't know what caused the four-inch-diameter, above-ground line that runs to the Irving Oil refinery to rupture.

Although emergency crews have deemed the situation "stable," clean-up of the colourless, highly flammable gas that can cause nausea, asphyxia and arrhythmia if inhaled continues.

As a result, the evacuation remains in place for about 65 people who live in the area.

'The priority for all operational crews and responders remains public safety and environmental protection.' - Saint John EMO

Bayside Drive, a major east Saint John artery, also remains closed to all traffic between the Courtenay Bay Causeway and Red Head Road, causing major traffic snarls on Loch Lomond Road and Champlain Drive.

"The priority for all operational crews and responders remains public safety and environmental protection," the Saint John Emergency Measures Organization said in a statement issued late Tuesday afternoon.

Emergency crews are focusing on safely removing any remaining liquid butane or vapours from the pipeline and cleaning up the liquid butane that accumulated on the ground, EMO said.

"Equipment is being assembled to complete these operations in a manner that is both safe and efficient," and air monitoring is ongoing.

Mark Sherman, Irving Oil vp, COO

Mark Sherman, Irving Oil's vice-president and chief operating officer, said the company likes to 'err on the side of caution' with any leaks, big or small. (CBC)

Once the Department of Environment investigates the leak, it will turn its file over to the Department of Justice and Public Safety, which is responsible for laying charges, said Chiasson.

"For now it is still too early to tell if that will be the case," he said.

"It has not been determined at this point what remedial action will be required," he added.

Pipeline inspected 'regularly'

On Tuesday, Mark Sherman, vice-president and chief operating officer of Irving Oil, could not say exactly how much butane leaked, but said it appeared to be a "very small amount."

The pipeline holds more than 17,000 litres. The refinery uses the butane as an additive to pressurize gasoline for vehicles during the colder months.

Sherman suspects the pipe sustained a "small freeze split," which he believes should be easy to repair once the clean-up is complete and it's safe for workers.

The pipeline is inspected by Irving employees "regularly," he said.

When asked to elaborate, Sherman said he didn't know all the specifics for that particular pipeline, but said it would be inspected annually for thickness and on a "more regular basis" via "physical walk throughs."

"Because it crosses multiple boundaries, it's part of the Energy Utilities Board pipeline network, so there's some obligations there," he said.

"So it's part of our regular monitoring process and our reliability program on all our pipelines."