The Oak Forest family of a technical surveyor killed last year after falling more than 100 feet from scaffolding at the in-progress construction site of a cancer research center at UChicago Medicine reached a $23.5 million settlement with two construction companies, the family’s attorney announced this week.

The family of David O’Donnell filed a wrongful death lawsuit last June after he fell about nine stories during high winds. O’Donnell, 27, died from the fall, while his co-worker Jeffrey Spyrka suffered injuries his attorneys called “severe, life-altering physical and psychological trauma.” The Spyrka family’s lawsuit against the companies is ongoing.

“The profound loss (the O’Donnell family) have endured following David’s tragic death is truly unimaginable,” said attorney Louis Anthony Cairo in a news release. “We sincerely hope that this settlement provides a foundation for healing and allows the family to begin moving forward.”

Cairo said the two companies named in the lawsuit — the general contractor, Turner Construction Co., and a subcontractor in charge of erecting the scaffolding system, Adjusted Concrete Construction — resolved the case during a full-day mediation session, avoiding a “protracted and costly litigation.”

Representatives from Turner Construction and Adjusted Concrete didn’t immediately respond to a request for comment. They’ve both previously said they support investigations into the incident.

The lawsuit, filed in Cook County Circuit Court, had accused the companies of not taking proper safety measures and putting workers in danger through a series of “negligent and careless acts.”

Cairo said preliminary investigations indicated “serious deficiencies” in the scaffold system, which was designed to withstand winds up to 85 mph, but failed due to a corner separating when gusts hit 44 mph.

Attorneys had said the southwest corner was held together with a piece of plywood with nails on top.

“The multiple failures in constructing the suspended scaffold system, along with the repeated daily failures to inspect the scaffold by a competent person, were inexcusable,” Cairo said.

“The serious nature of the liability created a tipping point in the negotiations that drove the result that we were able to reach for the O’Donnell family.”

O’Donnell, who was raised in Oak Forest, is survived by his parents and three brothers.

One of his brothers described him as “wicked smart” and “immensely funny,” saying he enjoyed golf, camping, the White Sox and the Chicago skyline.