BYRON -- A standalone restroom at Bethany State Reservoir and Park was leveled Tuesday afternoon in an explosion authorities say could have seriously injured or killed someone if visitors had been nearby.
The bomb squad from the Alameda County Sheriff's Office responded about 2:30 p.m. to the park about eight miles northeast of Livermore after a caller reported a restroom building at the west end of the park had been destroyed by what appeared to be an explosion, according to officials from the Northern California Regional Intelligence Center. Authorities arrived to find the building leveled and a debris field about 100 yards in all directions, with pieces of concrete the size of grapefruits as far as 200 feet from the center of the blast.
The restroom, which was 12 feet long and 6 feet wide, was made of 6 inch-thick steel-reinforced concrete, and bomb squad personnel say the roof weighed between 1,500 and 2,000 pounds. The blast was so forceful it left an imprint of the front metal door on an adjacent concrete wall, officials said.
According to NCRIC authorities, the explosive device was a radial car tire filled with several pounds of gunpowder, compressed and sealed using large, metal bands, then wrapped in duct tape. While the design was simple, officials said, it was also highly effective, and could have easily injured or killed anyone who might have been near the restroom when the bomb went off.
The device appeared to be fused to go off at a particular time, authorities said, and tire tracks near the debris field suggest they may have belonged to whoever placed and set the explosive. Information about a suspect or a motive was unavailable Wednesday afternoon.
Alameda County Sheriff's officials notified the Federal Bureau of Investigations, Northern California Regional Intelligence Center and California State Parks Police, and a joint investigation is ongoing, officials said.