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The explosion that changed milling

The evening of May 2, 1878 at the Washburn “A” mill – the largest mill of its time in the U.S. – began as any other as the day shift crews left the Minneapolis mill and the smaller night crew clocked in.

But at around 7 p.m. – flour dust in the air ignited and the mill exploded. The blast blew the roof off the A mill, leveled five other mills and engulfed several city blocks in flames.

Here’s how one reporter dramatically described the event:

“Flame and smoke in dense volumes leaped hundreds of feet heavenward, and the word went from lip to lip, almost with the rapidity of lightning, that the Washburn mill, which has long and justly been the pride of Minneapolis, had exploded and was destroyed … It was a night of horror in Minneapolis.” – St. Paul Globe – May 4, 1878.

Sadly, the massive explosion killed 18 workers.

When Cadwallader C. Washburn – the founder of General Mills – heard the news, he hopped a train from Wisconsin (he was the Governor of Wisconsin at the time) to view the wreckage.

His immediate concern was for the families of the employees – and others in the area – who were killed or injured by the explosion. Washburn initiated a fund to help them and was eventually revealed to be the fund’s most generous contributor. He also made sure the workers displaced by the loss of the mill could continue working in another mill.

At the site, Washburn walked through the rubble, marking off the foundation in the ashes for an even bigger mill to be built on the remains of the old one.

But, determined to prevent a similar disaster in the future, Washburn requested a demonstration of a new device that he’d heard would successfully deal with the millstone exhaust and prevent flour dust from clouding the air.

It was engineer William de la Barre who hauled the machine from Philadelphia to Minneapolis to show Washburn and business partner John Crosby its merits. The two leaders were completely satisfied, and asked for it to be immediately installed in the “C” mill, and eventually in their other mills.

Washburn also shared these innovations with his competitors. Once the devices – eventually called “dust collectors” – were installed in other Minneapolis mills, the flour milling process and industry became much safer.

By mid-1880, the new “A” mill was fully functioning. Built with state-of the-art steel rollers and then middlings purifiers (an invention that made flour whiter), capacity was increased and costs were lowered.

The “A” Mill continued to grind wheat until 1965 when General Mills closed the facility. A fire in 1991 destroyed much of the building and all the remaining original equipment. The Minnesota Historical Society began to renovate the property in 2001, which was already listed as a National Historic Landmark.

In 2003, the building was re-opened, this time as the Mill City Museum.

So today, you can tour the ruins of the Washburn “A” mill yourself.

Editor’s note: Reports suggest that the mill explosion prompted a concern in Cadwallader Washburn about the children of workers injured or killed in industrial accidents. As a result, after his death in 1882, Washburn’s will established an orphanage – the Washburn Memorial Orphan Asylum.

Over the years, the organization changed names several times. From the Washburn Foster Home Placement Agency to the Washburn Memorial Clinic, and then from the Washburn Child Guidance Center to its name today – the Washburn Center for Children. It is the leading provider of services for children with social, emotional and behavioral problems in the Twin Cities.

Have a question about General Mills’ history? Send our Archives team an email.

Visit our History page on GeneralMills.com for more information about our past.


Suzy Goodsell was a manager for internal communications and Archives for General Mills, based in Minneapolis, Minn. She wrote articles for the company’s intranet home page and worked to get employees more engaged in company history. She worked for General Mills from 2003-2012.

Suzy Goodsell

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