The RCMP-led Integrated National Security Enforcement Team is trying to determine exactly what happened Saturday night at the site southwest of Crossfield, about 50 kilometres north of Calgary.
Mounties say the small fire happened at an oilfield pipe riser and was contained to some plug openings connected to the valves of the pipes.
"At this point, nothing shows that this is a co-ordinated or a planned thing. At this point we perceive it to be just a mischief by some individual," RCMP Staff Sgt. Denis Rivais, a spokesman for the national security team, said Monday.
Rivais said the pipe riser is where sour gas gets fed into a hub and shipped to the rest of the province.
No one was hurt and the flow of natural gas to the site was closed by Direct Energy workers. Gas already in the pipes was allowed to burn off.
Company officials had air monitoring staff in the area throughout the night.
The integrated team is made up of specially trained members of the RCMP and other law enforcement and national security partners at the federal, provincial and municipal levels. It investigates all national security criminal threats.
Rivais said one of the unit's mandates is to review threats to critical infrastructure, so its investigators were originally called about the damage to the pipe riser.
"Since we began the investigation, rather than hand it off to someone else, we're continuing on with the lead."
The opening of an Alberta office for the integrated team was announced earlier this year, but the unit existed in an earlier form as the National Security Enforcement section. The difference is that the team now has CSIS, the Canada Border Services Agency and representatives from police forces in Calgary and Edmonton as partners.
Assistant RCMP Commissioner Gilles Michaud said at the time the office opened that the key to effectively guarding the labyrinth of oil and natural gas wells, pipelines and refineries in Alberta would be to gather intelligence to prevent attacks before they happen.
He said the booming Alberta economy suggested an increased threat to its infrastructure.
There are about 400,000 kilometres of provincially regulated energy pipelines criss-crossing the province. That doesn't include federally regulated or smaller distribution pipelines.