A Saint John, N.B. boy nearly gave his grandfather a blast from the past on Monday when he brought home a rusty old hand grenade from the Second World War.

“I recognized it right off the bat,” said Ron McLean, the boy’s grandfather and a former member of the Canadian Forces.

McLean said his grandson found the hand grenade on nearby Mispec Beach, on the edge of Saint John Harbour. McLean called authorities immediately.

“It was rusted pretty bad,” he told CTV News. “The older it gets… that’s when they’re the most dangerous.”

Police evacuated the area and called in bomb technicians from nearby CFB Gagetown to safely dispose of the device. No one was injured during the operation.

It’s not the first time explosives have been found on the beaches of the Saint John Harbour. Two years ago, a couple strolling along the beach discovered a washed-up military crate containing an explosive marine location marker. Experts from CFB Gagetown safely disposed of the device.

Saint John historian Harold Wright said it was once legal for the Canadian military to dump faulty or waterlogged ammunition in the ocean.

“In 1945-46, there was a contract to take the ammunition out into the middle of the bay,” he told CTV News. “Ocean dumping was common, but ammunition was being illegally dumped inside and just outside Saint John Harbour.”

Wright said there are still ammunition stores sitting at the bottom of the harbour.

“What worries me is that more of this will wash ashore and someday a piece of it can go ‘kaboom’ and somebody can get hurt,” he said.

“There’s a lot more out there.”

With files from CTV Atlantic