Robert Palmer, 37, and Tamica Jeffers, 33, both admitted snorting heroin, according to court documents.
Police said both had "life-threatening" overdoses.
The couple's children, an 8-year-old boy and 5-year-old girl, were found in the play area.
"This is ridiculous. I mean, we have people sometimes that we find that have used heroin usually parked in the car that are in need of medical attention but this is unusual for the fact that they were supposed to be caring for two young children," Green Township Police Chief Bart West said.
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