(CBS) — Almost two dozen people have been treated for skin irritation – after someone sprayed mace or pepper-spray at an anniversary party on the South Side.

The couple is 50 years married. They were celebrating outdoors at a home in the Gage Park area – around 51st and Rockwell.

And about 11 p.m. Saturday – Chicago Police say someone sprayed a mace-like substance into the yard. Paramedics were called and adults and children were treated on the scene – and taken to hospitals.

Fire Department Spokesman Larry Langford says 23 in all were treated for skin irritation.

Police say no one’s in custody.

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