A massive drug bust in Southern California led to the confiscation of 18 pounds of fentanyl — enough to create four million lethal doses, authorities said.

The huge seizure amounted for half of the fentanyl snagged in Orange County this year, with investigators nabbing about $1.25-million worth of the deadly opioid last Wednesday, the Orange County Register reported.

“The threat this extremely potent drug poses to our community is increasing exponentially, not subsiding,” Orange County Sheriff Don Barnes said in a statement.

The sheriff’s office said they also seized a semi-automatic handgun, heroin, methamphetamine and $71,000 in cash.

Sheriff’s officials declined to reveal where the drugs were found but said the operation took place during the execution of a search warrant.

They arrested Rudolph Garcia, 60, on charges of drug possession, as well as being a felon in possession of a firearm. He is being held on $2 million bond, according to the report.

Health officials have warned that fentanyl is a growing threat to the public with deaths in the county attributed to the drug rising from 14 five years ago to 93 in 2018.