In the shadowy world of drug smuggling, even small changes can raise suspicions and result in serious consequences.

In May 2009, an importer who usually brought steel rods into Canada in containers suddenly switched to bales of cotton, and that was enough to prompt the Canada Border Services Agency in Halifax to take a closer look.

The suspicions raised by the unusual cargo led to many arrests and drug seizures around the world, after officials found more than 5,700 kilograms of hashish hidden behind a false wall in the shipping container.

The street value of the drugs was roughly $114.5-million and the single container found at the Port of Halifax was just the beginning of the story.

The seizure led police to evidence that allowed them to trace regular shipments of hashish bricks from Karachi, Pakistan to an address in Montreal.

The RCMP spearheaded what became an international investigation called Operation Celsius, which resulted in the takedown of global drug distribution network.

Roughly $860-million in drugs were seized around the world in connection to the investigation.

"The arrest of nine people and the seizure of 43 metric tonnes of hash in various countries," says Dominic Mallette of the Canada Border Services Agency. "Forty-three tonnes is enough hash to provide a daily dose for a city of 10,000 for 11 years."

Three employees were arrested at the Port of Montreal on April 18 of this year, along with others whom police say are connected to organized crime.

"Forty-three tonnes is enough hash to provide a daily dose for a city of 10,000 for 11 years, and is worth about $860-million," says Mallette.

Border service agents say they hope the seizures will lead to even bigger busts.

With files from CTV Atlantic's Ron Shaw