Agents say more than $2 million in fentanyl was seized from a car at a checkpoint along Interstate 8.
The drugs were found hidden inside the doors, gas tank and behind the seat.
"The narcotics totaled more than 192 pounds, enough to kill 48 million people," said Chief Patrol Agent Patricia McGurk-Daniel on Twitter.
Meanwhile, in Amado, Arizona troopers discovered near 230 pounds of fentanyl and 10 pounds of cocaine during a traffic stop on June 2.
The DEA reiterates that fentanyl is the deadliest drug facing this country. Officials say it’s 50 times more potent than heroin and just two milligrams, or about the amount that can fit on the tip of a pen, is considered a lethal dose.