SANTA ANA  (AP) — Southern California authorities say 18 pounds (8 kilograms) of fentanyl have been seized in Orange County — enough of the synthetic opioid to create four million lethal doses.

The Orange County Register reports the seizure last week yielded almost half the amount of fentanyl seized by authorities in the county during all of 2018 — a sign the drug is quickly growing into a substantial public threat.

Sheriff’s officials say investigators served a search warrant and arrested 60-year-old Rudolph Garcia on multiple drug charges. It wasn’t known if Garcia has an attorney.

Investigators also seized a semi-automatic handgun, heroin, methamphetamine, and $71,000 in cash.

According to the California Department of Public Health, deaths in Orange County attributed to fentanyl have risen from 14 five years ago to 93 in 2018.