Officials say several manhole covers have been stolen in the Tucson area, creating a hazard for the area's pedestrians.
The Pima County Regional Wastewater Reclamation Department tells KOLD-TV that all seven of the stolen covers have been replaced, but officials worry that more may disappear.
The department says people should call 911 immediately if they see someone tampering with the covers.
The Tucson Police Department and the Pima County Sheriff's Department say people should use caution when walking, jogging and driving.
Pima County Wastewater Deputy Director John Warner says some holes can be as deep as 30 feet and could cause car damage or even death. He says people could hit their head and hit or break arms and legs during the fall. They could also suffocate or drown.