On Thursday, Nebraska Gov. Pete Ricketts announced the bust, considered the largest in the state's history and one of the largest in the United States.
Authorities seized 118 pounds of fentanyl during a routine traffic stop April 26 on Interstate 80 near Kearney. Troopers became suspicious of a semi-truck driving on the shoulder lane, searched the vehicle and found drugs in a hidden compartment, according to Nebraska State Patrol Col. John Bolduc.
At first, troopers believed they had found mostly cocaine, but further testing showed it was all fentanyl.
Troopers did not immediately test the drugs due to the "dangerous nature of the substance," the Nebraska State Patrol said.
The drug can be a threat to anyone who comes into contact with it as it can be absorbed through the skin or accidentally inhaled.
The driver of the truck, Felipe Genao-Minaya, 46, and passenger, Nelson Nunez, 52, both of New Jersey, were arrested on suspicion of possession of a controlled substance with intent to deliver, the agency said.
The value of the drugs is estimated at more than $20 million.
The 118 pounds seized during the bust could kill about 26 million people, according to estimates by the DEA.
A lethal dosage of 2 milligrams of fentanyl can be lethal for most people, the agency said.
Fentanyl is a powerful opioid that is 50 to 100 times more potent than morphine and 30 to 50 times more potent than heroin.