Why the smell of vinegar shut down a Toronto library's historical newspaper archive

When Toronto Reference Library staff opened cabinets full of historic newspaper collections after COVID-19 closures they were met with a smell usually reserved for fish and chips. 

"We discovered a strong scent of vinegar," said Nancy Duncan, a manager at the library.

The odour was their first clue that they'd have to take action if they wanted to save the newspaper collection that was stored on tens of thousands of microfilm reels and microfiches.

From the 1950s through the early 1990s, most film was cellulose acetate-based and known as "safety film," because it replaced the highly unstable and flammable nitrate film widely used before it.

But in the years since, libraries, archives and collectors have discovered "safety film" actually poses a huge threat to film-based archives and collections because it eventually breaks down. An early indication is the smell of vinegar, which comes from acetic acid that the film gives off as it degrades. Eventually, the film shrinks and cracks until the image is lost.

The destructive and contagious chemical decay is aptly called "vinegar syndrome" — and it means the clock is ticking for those trying to preserve history from this era in Toronto, across the country and around the world. 

Luckily for the Toronto Reference Library, Duncan says its newspaper collection — which includes out of print publications like the Toronto Telegraph and back issues of community papers like the Etobicoke Guardian and Scarborough Mirror — was only in the early stages of vinegar syndrome.

"It might have accumulated because the cabinets were closed for a long period," she said, referring to library closures during the COVID-19 pandemic. 

"Our main goal is to preserve our local history collections and make them safe and accessible again as soon as possible."

Normally, the public can access the microform newspaper collection in the library's Toronto Star Newspaper Room, but the room has been closed since May because of the vinegar syndrome, and is expected to remain that way for at least two more months. 

The library's plan is to sort through its more than 50,000 microfilm reels and 700,000 microfiches to determine which ones are acetate film and which are polyester film — a newer film type that can last 500 years. At the same time, staff are working to figure out which parts of the newspaper collection aren't available elsewhere.

The rare records will be preserved by transferring them to polyester film so historians, genealogists and others can continue to view the newspapers in their original formatting. 

"We know it'll take at least another eight weeks to do the separation work and then the replacement work will continue beyond that," said Duncan.

The library plans to dispose of its acetate film collection after the rare film reels and microfiches have been copied over, in part due to health and safety concerns. In its most advanced state Duncan says vinegar syndrome can cause contact burns, as well as irritation to the nose and lungs.