ALAMEDA -- An explosive device was found and detonated by authorities at Crown Memorial Beach in Alameda on Sunday morning, police said.
The device, which appeared to be some sort of firework, was found on the ground about 10:30 a.m. by a park ranger who was doing maintenance work near the restrooms at Shoreline Drive and Park Street, said East Bay Regional Park District Lt. Jon King.
Portions of Crown Beach, Shoreline Drive and Park Street were closed during the investigation.
The Alameda County bomb squad responded to the scene and determined that the device was potentially explosive in nature. The device was safely detonated in place and no injuries were reported, King said.
"We're not exactly sure what it was, but it appears it was possibly some type of firework that was concealed," King said. "I understand it made a pretty loud sound when it was detonated."
As of 5:30 p.m., the park and nearby streets had been reopened. The incident remained under investigation on Sunday evening.
Anyone with information about the incident is asked to call police at 510-881-1833.
Contact Natalie Neysa Alund at 510-293-2469. Follow her at Twitter.com/nataliealund.