There are conflicting theories on what caused a powerful blast that tore through a lounge in a busy Playa del Carmen resort on Nov. 14, killing seven people including five Canadians.

From the start, Mexico’s state prosecutor and local officials said trapped gases from a nearby swamp ignited and blew up. However, on Nov. 16, investigators said they had found a ruptured sewer pipe about 10 metres from the site of the blast at the 676-room Grand Riviera Princess resort. They added that it was too early to definitively state the cause of the explosion.

University of Toronto Professor Emeritus Olev Trass (ChemE) told CBC News that the swamp gas scenario was likely.

Swamp gas, also known as marsh gas or landfill gas, is a biogas that is produced when organic material like dead vegetation rots in an oxygen-starved environment such as a swamp, marsh or peat bog.

“It is fairly likely indeed because it can collect underneath the hotel,” Trass said. “As any vegetable matter decays under conditions [where no air is present], they generate methane gas and that has to go somewhere.

“Normally it would go out into the atmosphere and nobody would be bothered by it, and you might see the occasional little bubble coming through the water and nothing else. But if you block off that access to the atmosphere, then it builds up and it simply builds up pressure … all you needed was a tiny spark and the whole thing would go up.”

Follow the link to read the full article on the CBC News website.