SAN DIEGO — Fentanyl is being called the single deadliest drug threat our nation has ever encountered, according to the Drug Enforcement Administration.

Joey Rubio comes to areas in San Diego that are forgotten or avoided, trying to get people off the streets and off of drugs. He started using heroin when he was 10, got involved in gangs and spent 35 years in and out of prison. He’s 63 years old now and has been sober for seven years, sharing his story with anyone who will listen.

“Once I got off the drugs, everything started coming together,” Rubio told one man while walking around.

Rubio has helped hundreds of people through his role with the McAlister Institute, a nonprofit focused on healing lives through recovery. It’s a dedication that breaks his heart sometimes.

“This disease of addiction, I hate this disease,” he said. “It’s tough.”

Rubio’s visits recently are more urgent. He has seen more people that he cares about die from fentanyl overdoses, and he desperately wants to save them before it’s too late.

When used correctly, fentanyl can help treat severe pain in emergency rooms and hospitals. According to UC Davis, it’s 50 to 100 times more powerful than morphine, and just two milligrams can cause overdose or death.

The DEA estimates more than 71,000 Americans died last year alone from fentanyl-linked overdoses and drug poisonings.

Jeanne McAlister founded the McAlister Institute in 1977. Even though she’s the CEO, she still has the hands-on approach of a caseworker.

McAlister is a recovering alcoholic and has been sober for 66 years. She said fentanyl use has skyrocketed, and despite measures to keep drugs away from their facilities, they’ve had to resuscitate two clients from otherwise lethal fentanyl overdoses in the past several months.

“It’s very scary because a lot of people don’t realize that they’re even using fentanyl, because they’re coating other drugs with it,” she said. “It’s almost like a death wish.”

McAlister Institute serves about one-third of the people seeking recovery treatment through San Diego County’s Behavioral Health Services department.

Dr. James Dunford, medical officer at McAlister Institute and professor emeritus of Emergency Medicine, said fentanyl use has skyrocketed among clients at their substance use disorder treatment programs, regardless of their housing status, and managing fentanyl withdrawal is more complicated than with heroin and other narcotics.

“Due to fentanyl’s remarkable potency, ease of use (smoking versus injecting heroin), low street cost and ready availability (versus street heroin), individuals with opioid use disorder seem to become addicted more quickly, consume resources faster and enter homelessness sooner,” Dunford said. “And when they seek treatment, they are often sicker, more emotionally unstable and require a higher level of care.”

Rubio believes the death toll is only going to get higher unless they finally accept help to get clean.

“A lot of these people don’t know that they put fentanyl in everything today,” he said. “You could smoke a joint of marijuana and it has fentanyl in it. I got a friend who smoked crack, and he died. It had fentanyl in it. And it’s sad, they have no idea of the danger they’re putting themselves in.”

It’s a hard fight, but Rubio is determined to never give up, using his story of sobriety to save as many people as he can.

“I try to change lives like somebody changed mine,” he said. “I believe everybody deserves a second chance. I was given thousands. I had people believing in me when I couldn’t yet believe in myself.”

Gov. Gavin Newsom is proposing to add $96 million in funding to this year’s budget to combat the fentanyl crisis, which would include initiatives to make Naloxone, a medicine that treats an opioid overdose, more accessible.