Film clips have surfaced of a 1915 disaster that left 844 people dead when a ship headed to a company picnic capsized in the Chicago river.

The first-known footage of the Eastland disaster was spotted by Jeff Nichols, a doctoral student at the University of Illinois at Chicago who was looking through seemingly unrelated material in the Netherlands on the first world war.

Nichols, who has lived in Chicago for 20 years, said he found the clips in Dutch newsreels. Title cards describing what happened precede them.

“It’s as easily recognisable to someone who cares about Chicago history as the Titanic, so I knew what I had right away,” Nichols told the Chicago Tribune. “I knew folks would go, ‘Wow,’ even if they had seen the clip before.”

The SS Eastland, which was carrying 2,500 people, turned on to its side while docked in the Chicago river in July 1915. It was one of five boats chartered that day to take Western Electric workers and their families and friends across Lake Michigan to a park in Michigan City, Indiana.

One 55-second clip shows first-responders and volunteers walking on the boat, and a second 30-second clip shows workers trying to right the ship at least a week later.

Frank Roumen, a collections manager with EYE Film Instituut Nederland, confirmed in an email sent to the Associated Press that the footage is in the institute’s archives.

Nichols posted links to the clips on the Facebook page of the Eastland Disaster Historical Society, which later put them on its website.

Chicagoans gather on a city pier to see the Eastland’s wreck in 1915. Photograph: Library of Congress

“It completely defeats the purpose to hoard the thing,” Nichols said. “It’s something that should be shared, and it’s easily shared with lots of folks.”

Ted Wachholz, the historical society’s chief historian, said photos of the disaster showed movie cameras on tripods, leading him to believe footage existed somewhere. Nichols said that after his initial discovery he found a copy of one of the clips in another museum, and he guessed that other copies could be out there.

“These [lost] films are discovered where you’d least expect them, so it’s not a surprise that it was in the Netherlands,” Nichols said. “If it were close at hand, then it would have been discovered a long time ago.”

The last known survivor of the Eastland disaster, 102-year-old Marion Eichholz, died in November.