Authorities responded to the 11000 block of Wilshire Boulevard after a patient found the device in the emergency room around 6:45 a.m., officials said. Police say it looked real. It was green and still had a pin in it.
"We treat it as if it was live. We made a safe zone within the facility to make sure all of our patients and staff are safe," said Department of Veterans Affairs Police Chief Ed Casey.
The emergency room area was evacuated as a bomb squad examined the object.
"I was a little nervous for one thing," said Carl Lewis. "Being a veteran, you know what a hand grenade can do."
Police are trying to determine who left the device. A 66-year-old man, who is a veteran and is familiar to hospital employees, was detained for questioning.