The destruction of Halifax was the last thing hundreds of people ever saw as the largest mass blinding in Canadian history profoundly changed the way visually impaired Canadians live.

People heading to work and school 99 years ago Tuesday heard or saw the relief ship Imo bang into the Mont Blanc on a bright December morning. Despite the Great War's routine carnage in Europe, North America had seen little first-hand violence, so few people thought to be afraid.

A fire opened up on the Mont Blanc as the beat-up French ship drifted toward the Halifax shoreline. Benzoyl drums rocketed off the deck and exploded like fireworks, drawing curious crowds to windows and the waterfront.

Hull blasted 300 metres skyward

At 9:04 a.m., the fire lit the fuse on tonnes of TNT, gun cotton and picric acid stored on the Mont Blanc. The war-bound ammunition tore the mighty ship to shards in a 5,000 C inferno, blasting its ruined hull 300 metres into the sky. The shock wave smashed through the city at 5,400 km/h and a following tsunami dragged people into the churning harbour. Four per cent of the city's 50,000 people died in the same instant.

Emmanuel Church in Dartmouth was knocked down by the explosion. (Courtesy Maritime Museum of the Atlantic)

Shattered glass and flying debris stole sight from more than 1,000 residents. One in 50 people in Halifax were blinded that day or suffered serious eye damage. Doctors and nurses removed or treated damaged eyes from hundreds of people in the two weeks after the deadly blast. Some 206 people lost one eye and dozens lost both. Hundreds more were left with glass embedded in their eyes.

Nova Scotia poised to help

The mass blinding helped birth the Canadian National Institute for the Blind. Jane Beaumont, CNIB's volunteer archivist, says the scale of the disaster led to fundamental changes.

"It was a big enough event that it compelled people who cared and governments to take notice that we had needs of people with vision loss," she says.

One of those people took a break from his work as a mechanic to tell CBC News what happened in this 1957 clip.

Victims remember the tragedy of the Halifax Explosion. 8:54

Beaumont says the Canadian Free Library for the Blind had been founded a decade earlier in Ontario. It collected braille books and shared them with other blind readers. By the start of the Great War, the renamed Canadian National Library for the Blind was sharing books across Canada, as well as teaching people how to read braille.

Nova Scotia had long been a North American leader in care for people who are blind and so was strangely poised to deal with the mass blinding. The well-regarded Halifax School for the Blind had been operating since 1867, Beaumont says, and in 1882 Nova Scotia passed an act ensuring free education for blind people.

"There's a long history in Nova Scotia of supporting people with vision loss," she says.

Lt. Victor Magnus had his camera at the ready in the aftermath of the Halifax Explosion. (Victor Magnus)

The CNIB didn't start until 1918, but was formed in the forge of the 1917 Halifax Explosion. "There was nothing for them and very little help. That's how the library evolved into the CNIB," she says.

Comparing England to Canada

After the explosion, the proto-CNIB raised money and sent it to help with the relief. The Halifax Relief Commission provided pensions to people who had lost part or all of their sight, and Beaumont has found evidence that CNIB administered the fund at some point.

Troop ships returning maimed soldiers from Europe added to the count of Nova Scotians learning to live with blindness. Those military people had the chance to directly compare care in England to care in Canada, and found Canada far behind.

Soldiers search the ruins after the disaster. (Courtesy Maritime Command useum)

"It was the model of what was available in England that really lead to the creation of CNIB," Beaumont says. "A group of people who had lost their sight understood what could be done if they had the right rehabilitation services."

Canada sent people to England to learn those techniques. The biggest change was the focus on integration. Instead of working with people born sightless or who had lost it to disease, suddenly there were hundreds of people of all ages and backgrounds who lost sight unexpectedly in the middle of their lives.

Living independently

"It was an early case of an institution providing the necessary skills to get around the community and live independently. CNIB is still all about independence and getting people the skills and confidence to live an independent life, work in the workforce, bring up their children — do everything that the rest of us do," Beaumont says.

The Imo survived the explosion. You can read the large 'Belgian Relief' sign on its side. In 1921, a drunk captain crashed it into rocks off the Falkland Islands, where it sank in ruin. (Nova Scotia Archives & Record Management/Canadian Press)

Those proto-CNIB volunteers helped people learn to read braille, how to knit, to use washing machines, bread mixers and other tools to make post-sight life easier. Others arranged classes on life without vision and social gatherings where common problems could be tackled collectively. Women-run groups realized the problems were more than physical and organized picnics, boat rides and music to bring together the recently blinded and their families.

"Ninety-nine years later, CNIB is continuing our commitment to helping Nova Scotians deal with the emotional and social side of vision loss, while building the skills to do everyday tasks with confidence," says Crystal Legere, CNIB's manager of vision rehabilitation services in Nova Scotia.

CNIB has changed, too, now helping people all over Canada. It remains Nova Scotia's largest provider of vision rehabilitation for the 13,000 people who are blind or partially sighted.

Where to mark the 99th anniversary in Halifax

Halifax will mark the 99th anniversary of the Halifax Explosion on Tuesday. As always, the official service is set to take place at the Fort Needham Memorial Park bell tower, just up the hill from where the Mont Blanc exploded. It starts at 8:55 a.m. and ends around 9:20 a.m.

City hall will sound its tower bell for a minute at 9:05 a.m. ringing it alongside church bells, the Halifax Citadel cannon, and ships' horns and sirens. There are a few other events that day:

9:30 a.m.: public reception at the Needham Community Centre (3372 Devonshire Ave.)

10 a.m.: Halifax Regional Fire Services memorial event, fire station 4 (5830 Lady Hammond Rd.)

11 a.m.: Service of remembrance at Pinehill Park. The park is at the intersection of Albro Lake Road and Pinecrest Drive.

You'll find more information on the Halifax Explosion events and history here, and plans for the 100th anniversary here.