One in five inmates at the Hennepin County jail had a history of opioid use or abuse, and of that group, nearly all were actively using opioids at the time they were jailed, according to a one-day snapshot of the jail’s population.

“The numbers are staggering,” Hennepin County Sheriff Rich Stanek said at a news conference Tuesday.

Jail nurses interviewed the 851 inmates at the jail on Dec. 6, 2017.

Of those, 173 inmates (20 percent) self-reported use or abuse of opioids. Of the 173, 166 were actively using opioids when they came into the jail, said Jason White, the jail’s nurse manager.

The survey found that 111 of the 173 inmates (64 percent) had previously overdosed on opioids.

“I know one thing for sure: We need to get ahead of this crisis,” Stanek said. “It is the deadliest drug epidemic in our nation’s history, and we need to do more to prevent opioid abuse way before it begins. We need to provide more drug treatment alternatives.”

Stanek said the survey found that administering naloxone was crucial to keeping people alive after an overdose.

“An astonishing 95 percent — that’s 105 out of 111 inmates who have overdosed on at least one occasion — have been administered a lifesaving dose of naloxone,” Stanek said.

He said that before the study, his office didn’t know how many people who overdosed got naloxone.

Despite the widespread use of opioids, the study found, only 18 of the jail’s 851 inmates had undergone inpatient addiction treatment.

The opioid users also appeared to have a mental illness. Of the 173 inmates who used or abused opioids, 128 (74 percent) had some degree of mental illness.

Stanek said that on National Night Out on August 7, sheriff’s deputies will visit neighborhood parties, educating people about the opioid epidemic and handing out medication disposal bags to residents.

“We know that 70 percent of prescription drug abusers say they obtained their supplies of prescription medications from family and friends,” he said. “Too many people are overdosing; there are far too many people dying. We want to help save lives by helping on National Night Out.”