Civil rights attorney Ben Crump filed a lawsuit against an Illinois hospital after a woman died when she spent nearly seven hours trapped on the facility’s roof, causing her body temperature to drop to 50 degrees.

Chelsea Adolphus, 28, left her hospital room at Vista Medical Center East in Waukegan around 2 a.m. on Jan. 23 and somehow made her way to the roof, where she remained, wearing only a gown, until roughly 8:45 a.m., Lake County Coroner Jennifer Banek told reporters at a press conference. Temperatures in the Chicago area that morning were in the low 20s and felt like 10 degrees.

Once Adolphus was discovered, hospital staff rushed her to the emergency department where they spent several hours trying to warm her body, Banek said. But those efforts failed and doctors pronounced her dead. The preliminary cause of death is hypothermia, according to Banek.

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Officials are trying to figure out how Adolphus got up to the roof and why it took so long for hospital staff to realize she was missing. Crump said in a post on X (formerly Twitter) that Adolphus “wandered through an unsecured door” and then became locked out. The attorney called the situation “unacceptable negligence.”

“A hospital — a place meant for healing — became Chelsea’s death trap,” he wrote, adding he wants the hospital “accountable for her preventable death.”

Adolphus had been admitted to the hospital the day before for unspecified medical issues.

Banek said since 2023 in her job as a coroner she has “voiced my concerns about the lack of care and safety measures in place” at the hospital. She said the hospital has lacked blood supply and staff to treat trauma patients. Just days before Adolphus’ death, Banek pointed out on her Facebook page that the hospital’s parent company, American Healthcare Systems, furloughed about 70 employees.