100 cannonballs at Fortress of Louisbourg might contain gunpowder, but will be safely detonated

Among the millions of artifacts catalogued and carefully stored at the Fortress of Louisbourg in Nova Scotia, are 600 cannonballs sitting on wooden shelves.

The cannonballs have been there for decades, but staff at the national historic site recently began questioning whether the relics are actually dangerous and reached out to the Canadian Forces in Halifax for their expertise.

"They were just curious if any of them had any explosives or [if they] pose any risk," said Barry Noseworthy of the Fleet Diving Unit, which handles unexploded ordnance.

"They're really old. They've been dug up over the years and stored in this building since the early '60s."

After conducting an initial examination last month, Noseworthy and his team are now busy collecting the roughly 100 cannonballs believed to contain explosive black powder or gunpowder.

"I've never dealt with anything this old, so we hate to see them go," said Noseworthy. "But for public safety and to minimize the risk, we unfortunately have to blow them up."

Noseworthy said black powder is the earliest known chemical explosive and is relatively stable as it requires a fuse to detonate.

He said though the cannonballs won't all be detonated at the same time, it should create a "nice, good bang."

As part of their removal, disposal technicians are expected to transport the cannonballs to CFB Gagetown in New Brunswick on Friday. 

The cannonballs are expected to be destroyed in a controlled detonation Monday. 

Members of the diving unit will not be removing fragments of cannonballs found on the fortress property — ones that were likely used in battle — or the solid steel cannonballs that were typically fired in hopes of damaging enemy ships.

Noseworthy said these items are relics from battles past, including wars waged between the French and the British in the mid-1700s.