Santa Ana, California — Southern California authorities say 18 pounds of fentanyl have been seized in Orange County. It's enough of the synthetic opioid to create four million lethal doses and has an estimated street value of more than $1.25 million. 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 Rudolph Garcia, 60, 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.

#OCSDPIO The threat of fentanyl is increasing exponentially. So far in 2019, teams have seized more than 100 pounds of the deadly drug, setting the pace to more than double fentanyl seizures for the third year. 👇 pic.twitter.com/RW6lIPEpTc — OC Sheriff, CA (@OCSheriff) October 18, 2019

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.

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

In 2017, there were 47,000 opioid deaths — that's more Americans than were killed in vehicle accidents or by firearms. Fentanyl is like rocket fuel in the sharp rise of the crisis. It is a painkiller invented in the 1960s and used to relieve the agony of advanced cancer. It is 50 times more potent than heroin.

Fentanyl has been linked to the deaths of musicians Mac Miller and Prince — and took the life of Angels pitcher Tyler Skaggs.

The total economic cost of the crisis, declared a federal public health emergency in 2017, reached at least $631 billion from 2015 to 2018, an analysis from the Society of Actuaries (SOA) found. That is more than the gross domestic product of such countries as Belgium, Sweden and Taiwan.

Three drug distributors — AmerisourceBergen, Cardinal Health and McKesson Corporation — and two manufacturers — Johnson & Johnson and Teva — have reportedly offered a total of $50 billion to settle more than 2,000 lawsuits filed by towns, cities, counties and tribal governments and avoid going to trial.

Megan Cerullo contributed to this report.