AVONDALE, Ariz. -- Firefighters, police and eventually a SWAT unit converged on an Avondale playground after somebody reported suspicious objects in a rock-climbing structure.
It happened Wednesday night in the Crystal Point neighborhood in the area of Avondale Avenue and McDowell Road.
Officers taped off a block and told residents to stay inside while SWAT investigated. Nobody was evacuated.
Neighbors reportedly saw bomb squad technicians and Avondale SWAT team members putting objects into paper bags and then examining them..
Avondale police said a father and son were working on a school project involving dry ice in bottles.
Apparently the boy suffered a minor injury when he got too close to a bottle as it burst.
The dad immediately took his son to a local hospital as a precaution, but they left the park so quickly they inadvertently left a bottle of dry ice behind.
The Maricopa County Sheriff's Office safely burst that bottle.
Police said detectives talked to the father and son and both are fine. No charges will be filed.
It was several hours before officers cleared the scene.