Stay up to date on East Bay news by downloading our mobile app for free. Get it from the Apple app store or the Google Play store.

ALAMEDA — An old mortar round that was possibly still active was found Monday afternoon during work on the new Jean Sweeney Open Space Park, prompting the Alameda County bomb squad to destroy it with a controlled explosion.

No one was hurt during the incident, Alameda police Lt. Hoshmand Durani said.

A caller reported the device just after 2 p.m. at Atlantic Avenue and Constitution Way, where crews are constructing the Cross Alameda Trail as part of the the new park.

A 150-foot area around the ordnance was evacuated and cordoned off, Durani said.

Like the Alameda Journal Facebook page for neighborhood news and conversation from Alameda and beyond.

The Alameda County Sheriff’s Office Explosive Ordinance Disposal Squad detonated it at the scene after determining the device still might be active.

Along with Alameda police and the county bomb squad, the Alameda Fire Department responded.

Details such as the device’s size and possible age were not available.

Just how the mortar round ended up at the site, which is former railroad property where homeless people were recently encamped, also was unknown.

Like our Facebook page for more conversation and news coverage from the East Bay and beyond.