The Bay Area Rapid Transport police officers and medical personnel were dispatched to a BART train at the Fremont Station due to a report of an unresponsive man.
According to the police, they found a 26-year-old man suffering from a possible drug overdose.
Officer said two doses of Narcan, a drug that can reverse overdoses, were administered, but the victim was pronounced at the scene.
Police said foul play is not suspected at this time.