COLUMBUS, Ohio (AP) — Ohio launched a $1.6 million study Thursday that aims to identify the genetic markers that separate people likely to develop opioid addiction from people somehow immune to the painkillers’ addictive properties.

Republican Attorney General Dave Yost, who oversees scientists at the Bureau of Criminal Investigation, is spearheading the effort, which is expected to take about 18 months.

It will include a study of patient swabs collected at emergency rooms at the University of Cincinnati and Ohio State University hospitals and related work by a panel of nine scientists.

At a Statehouse news conference announcing the effort, Yost said the Ohio study will build on scientific groundwork that already established a genetic basis for who gets addicted and who doesn’t.

“This is not a matter of how well you can handle things or how well-integrated your personality is — it’s a matter of chemistry,” he said.

He has tapped Dr. Jon Sprague, an eminent scholar at BCI, to lead that panel, dubbed the Scientific Committee on Opioid Prevention and Education, or SCOPE. Sprague is also director of the state’s Center for the Future of Forensic Science.

Sprague said no one yet knows which genes lead to addiction. The task force he is leading, which began meeting in June, is seeking to identify the circumstantial, environmental, social, behavioral and psychological factors that incline some people to substance use disorder.

He said all reactions to opioids, which can include prescription painkillers, heroin and illicit fentanyl, are important — even being unaffected by them.

“We want to know why it is that two people can take the same drug in the same dosage and only one becomes addicted,” he said. “We want to know how to blunt opioids’ harmful effects.”

Dr. Caroline Freiermuth, an associate professor of emergency medicine at the University of Cincinnati, said swabs will be collected from different groups: those never exposed to opioids, those previously exposed who never developed opioid use disorder, those currently exposed on a chronic basis who never developed the disorder, and those currently with the disorder. No personal identifying information will be revealed.

Ohio has been among the hardest hit in a national scourge, with a record 4,854 unintentional fatal overdoses in 2017, the most recent year for which statewide data is available.

National opioid litigation in which more than 2,000 cities, counties, tribal governments and unions are seeking to hold the pharmaceutical industry responsible for the epidemic is also focused in Ohio.

A judge in Cleveland is overseeing the massive case, which is set to begin Oct. 21 with a bellwether trial involving Cuyahoga and Summit counties.

Yost, who is separately pursuing a state lawsuit against the drug industry, said he hopes the scientific effort can help begin to reduce the number of people who become addicted each year.

“Once we do that, the unsung heroes on the front lines who are doing the treatment will actually be able to get their arms around this and to see progress, instead of drowning under the continuing flood,” he said.

Steven Marcalus, founder and CEO of TOPGx LLC, which specializes in gene science around drugs, a field called pharmacogenomics, said he hopes Ohio can marshal existing data and resources to come up with a genetic marker that a person could carry through life, like a risk for heart disease or diabetes, and provide to doctors and other medical professionals.

“We all are hoping the model will uncover information for us that says we can put a predictive model together, even for consumers, and say, ‘What is my risk of becoming an opioid addict?'” he said. “The eventual goal is that doctors could screen patients for this.”