Pipe explosion injures12 at East Bay factory

No chemicals were involved in the explosion, and there was no fire, Munoz said. It was not immediately clear what caused the explosion, but it happened during the pipe-making process as workers were pouring a substance into a mold, Munoz said. The 24-hour plant was not evacuated and operations were not shut down, said Union City Police Capt. Connie Van Putten.

Four injured men who suffered cuts, burns and smoke inhalation were transported to Eden Medical Center in Castro Valley. They were listed in fair condition Wednesday evening, said hospital spokeswoman Cassandra Phelps.

One man, Jose Delgado, 27, of Hayward, was later transferred to Alta Bates Medical Center's burn unit in Berkeley for treatment to burns on his face and hands, Phelps said. The other patients are Robert Campbell, 35, of Martinez, Ricardo Mejia, 30, of Hayward, and Gonzalo Hernandez, 21, of Oakland.

Four others were sent to St. Rose Hospital in Hayward, while the remaining four went to Kaiser Permanente Medical Center in Hayward. All eight suffered minor injuries, said Brad Shehan, a spokesman for American Medical Response.

The factory is located in an industrial area of Union City, about 12 miles southeast of Oakland. A counseling center was set up for family members across the street at Alpine Awards, which makes school, corporate and sports league trophies and other awards.

About 40-50 people gathered there following the accident, said Yolanda Murray, an employee of Alpine Awards who heard the explosion.

"There were just two tremendously loud explosions," Murray said. "It kind of felt like an earthquake at first, but I knew it wasn't because it happened too fast. It shook the windows. I wish it would have been an earthquake."<