Calgary-based oil companies Canadian Natural Resources Limited (CNRL), Penn West Exploration and Husky Energy account for close to 30 per cent of incidents publicly reported to the Alberta Energy Regulator, according to a Radio-Canada analysis.

More than 1,000 incidents, ranging from June 2013 to now, are listed on the AER database.

It includes reportable incidents like releases of hydrogen sulphide and hydrocarbons, or instances of contaminating bodies of water.

CNRL accounted for 137 reported incidents as of last Friday, Penn West for 82 and Husky Energy for 81.

Some energy giants didn't appear as often in these statistics. Imperial Oil accounted for 14 incidents while Suncor Energy was responsible for five.

Most incidents were related to pipelines. They include minor incidents, but also more serious ones such as Nexen's five million litre spill in July near Fort McMurray and the one million litre leak around CNRL's Primrose site in 2013.

Gaétan Caron, a fellow at the School of Public Policy at the University of Calgary, said that company size may be linked to the number of incidents but other factors may also be in play.

"A company ... with little culture of safety, or that is less conscious of the environmental impact of their operations, is more likely to appear in such a database," said Caron.

Greenpeace, companies react

Mike Hudema, a climate and energy campaigner at Greenpeace, said companies appearing repeatedly in the database should be punished.

"The government really should be putting a stop to their operations if they are not able to operate them safely," said Hudema.

"It's just a matter of time before we have a major disaster ... we are putting the environment at risk, we are putting the communities at risk."

Canadian Natural Resources spokeswoman Julia Woo said the vast majority of incidents mentioned in the database were of very low consequence, with no long-term effects to the environment.

"Our goal is to have zero incidents," said Woo. "When rare events occur, such as equipment malfunction that results in an incident, we have safety and environmental management systems in place to quickly manage these events." 

In a statement Husky Energy said that it takes all incidents seriously and responds appropriately. Penn West declined the opportunity to comment.

According to another database, Penn West has been issued seven suspension notices since July 2014, CNRL has received five and three have been issued to Husky Energy.