San Jose, Calif.-based PayPal, an, closed the building on Wednesday as FBI agents and local police investigated, said eBay spokesman Hani Durzi. The blast occurred at about 7:25 p.m., and at that time about 45 employees occupied the building, said Durzi.
The explosion triggered the security alarm and officials from the San Jose Fire department later ordered the building, which is typically occupied by about 1,900, to be evacuated. Employees are scheduled to return to work tomorrow, Durzi said. He added that PayPal's operations were never interrupted.
"We have at this point no reason to believe that this was anything other than an isolated incident," Durzi said. "The most important point is that we continue to provide a safe and secure work environment for our employees."
Durzi said he was unaware whether authorities have identified a suspect. Calls to the San Jose Police Department and the FBI were not immediately returned.
Capt. Jose Guerrero, of the San Jose Fire Department, said it's believed that the device "was not highly sophisticated." Authorities have called in the federal Bureau of Alcohol, Tobacco, Firearms and Explosives to help identify the explosive.