Twenty-two police officers were injured during the violent “Patriots Day” rally that took place in Berkeley on April 15, according to Berkeley Police Department spokesperson Sgt. Andrew Frankel.

One officer sustained a knee injury while the remaining 21 suffered either hearing loss due to their proximity to explosive devices or were exposed to a caustic chemical. No officers were hospitalized, Frankel said, but there are a number of officers still dealing with tinnitus and seeking treatment for their injuries.

Frankel said the bulk of BPD officers were present at the rally. One hundred and eighty officers from Oakland Police Department also provided mutual aid. BPD may only call for mutual aid if more than 50 percent of its officers are working, Frankel said.

But many have criticized officers for not preventing or immediately addressing much of the violence taking place on Saturday.

In preparation for the event, the city of Berkeley banned sticks, pipes, poles, pepper spray, eggs and any other instrument that could be used as an “implement of riot” from Martin Luther King Jr. Civic Center Park, where the rally began. But Joe Rothenbuhler, a San Francisco resident attending the rally, said the checkpoint in the park was “kind of a joke” and people were able to smuggle in prohibited materials.

He added that throughout the event, police repeatedly failed to intervene when altercations took place and when M-80s were thrown.

“The cops’ job is to keep order and they didn’t do that,” Rothenbuhler said. “They didn’t do their jobs.”

Police made 20 arrests at the event and are continuing to review video evidence to identify individuals involved in criminal activities. BPD is also soliciting photos and videos from the public.

“Our tactics are very deliberate we’re not going to go wading into a crowd and potentially put law-abiding citizens at risk.” Frankel said.

Jessica Lynn is the city news editor. Contact her at [email protected] and follow her on Twitter at @jessicailynn.