The police use of less-lethal weapons for crowd control during the George Floyd civil unrest in the Twin Cities led to a significant number of head, neck and face injuries, violating United Nations guidelines for such weapons, according to a study published Wednesday.

The study published in the New England Journal of Medicine said that the findings indicate "that under current practices, projectiles are not appropriate for crowd control."

Conducted by an interdisciplinary team from the University of Minnesota, the study was peer reviewed and published as a letter in the highly respected medical journal.

Floyd's death at the hands of Minneapolis police on May 25 triggered large demonstrations in the Twin Cities, some of them leading to confrontations with police, and the looting and burning of businesses. Police used tear gas and nonlethal projectiles as part of crowd control efforts to push back or disperse protesters.

The researchers found that more than half of 89 protesters treated at two Minneapolis hospitals were injured by crowd-control projectiles that are categorized as nonlethal.

According to United Nations guidelines, such projectiles should be aimed at lower extremities.

"What we were seeing is that people were harmed," said Rachel Hardeman, a professor of health and racial equity in the U's School of Public Health and one of the authors of the study.

Protesters and journalists have filed multiple lawsuits against Minneapolis police and the Minnesota State Patrol for injuries sustained during the protests. Complaints to Minneapolis police skyrocketed, and officials acknowledged last summer that some innocent civilians were injured during days of protests and unrest, but argued that the situation required force to maintain public safety and it was difficult to distinguish between peaceful protesters and those wishing to cause harm.

Minneapolis police spokesman John Elder said, "All uses of force are being reviewed by the department. Some of the uses of force have resulted in litigation. We are unable to comment on those at this time."

A spokesperson for the Minnesota Department of Public Safety, which oversees the State Patrol, did not immediately respond to requests for comment.

A spokesman for the Minnesota National Guard, which was deployed during the riots, said the Guard did not discharge nonlethal munitions during the civil unrest.

The study in the New England Journal examined injuries treated by clinics and hospitals in the M Health Fairview and Hennepin Healthcare systems, said Dr. David Darrow, a neurosurgeon and professor at the U of M Medical School, who was one of 14 authors of the study.

"We were surprised to see so many injuries to the face and the head and that got us worried," he said.

The study examined 6,626 medical records of patients treated between May 26 to June 15 in 2020 and found that of 89 who were injured in the protests and sought medical help, 45 were injured by projectiles, 32 were injured by chemical irritants and 12 suffered injuries from both projectiles and irritants.

Patients reported 41 injuries from rubber-coated bullets, seven from tear gas canisters, two from beanbags and seven from unknown projectiles.

Ten patients received eye trauma from projectiles, and seven of them required surgery. Sixteen patients received traumatic brain injuries.

Overall, 77 patients had what the study found were mild injuries, eight had moderate injuries and four were classified as severe.

Erika Kaske, a medical student and one of the authors, said the case that inspired the study was the injury of a teenager who received a depressed skull fracture during one of the first protests.

The teenager was a bystander. The youth had emergency brain surgery and has since fully recovered, she said. She said less-than-lethal weapons are inherently inaccurate because they move at lower speeds and are larger than lethal bullets.

She said there's no way to know if officers intended to hit people in the head with projectiles, but even when trying to use them correctly, serious injury can result.

"Our hope is to work with policymakers to prevent these type of injuries from happening again," she said.

As a result of a court order in August initiated by the state Department of Human Rights, Minneapolis police policy states that authorization for crowd control weapons can only come from the police chief or the chief's designee.

If there's an immediate danger, crowd control devices, except chemical munitions, may be used, but supervisors must be then notified and a report filed.

Last year, the United Nations human rights committee issued a report that said that kinetic impact projectiles (rubber-coated or plastic bullets) should aim at striking the lower abdomen or legs of a violent individual and only used where there's imminent threat of injury to either a law enforcement official or a member of the public.

The head, face and neck should not be targeted, the report said: "Targeting the face or head may result in skull fracture and brain injury, damage to the eyes, including permanent blindness, or even death," it said.

Randy Furst • 612-673-4224Geor