SAN MATEO (AP) – San Mateo police have cleared out a community park after a work crew found what a police spokesman is terming a “homemade explosive device.”

Police say a city maintenance worker found three clear plastic bottles containing liquid with a strong chemical smell at the city’s Casanova Park around 9 a.m. Saturday.

San Mateo police Sgt. David Norms says police and fire crews arrived at the park they determined the plastic liter bottles and their contents were consistent with an explosive device.

A San Mateo County hazmat team and the bomb squad was called in to the remove bottles. The park and a nearby residential area of about 15 homes was also evacuated.

No additional details have been released, but Norris says the bottles will be sent to the county’s forensic lab for analysis.

Investigators believe the discovery of the materials is an isolated incident. No arrests have been made and there were injuries.

(Copyright 2012 The Associated Press.)