Ohio residents will vote this fall on whether to legalize marijuana. Getty Images

The list of opponents to Ohio's marijuana legalization amendment reportedly expanded this week to include Cincinnati Children's Hospital Medical Center. The center, which is one of the largest pediatric hospitals in the country, joined the Ohioans Against Marijuana Monopolies coalition Monday in fighting the pro-pot group ResponsibleOhio.

“Our main concern is that kids could inadvertently consume edible products infused with marijuana,” spokesman Jim Feuer told the Cincinnati Business Courier, adding the hospital hasn't promised yet to spend any money on the "No on Issue 3" campaign, so named because the legalization amendment will likely be Issue 3 on the Nov. 3 ballot.

Representatives from the hospital joined ones from organizations like the Ohio Children's Hospital Association, Ohio Association of County Behavioral Health Authorities, Buckeye State Sheriff's Association and Ohio State Medical Association at a news conference Monday to kick off their efforts. They argued passing the amendment would enable a monopoly for the 10 predetermined growing sites and lead to Ohio having too many pot retail stores. But they said one of their biggest worries is that youth would come into contact with the products, the (Cleveland) Plain Dealer reported.

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The amendment would only allow adults older than 21 to buy and use pot themselves, but adults and children could use the drug for medical treatment with a prescription.

“We are concerned that making marijuana legally available to adults will result in increased access for teens and children, as well as causing teens to believe legalization equates to ‘safe,’ ” Sarah Denny, a physician at Nationwide Children’s Hospital in Columbus, which is also in the coalition, said in a statement to WKYC, Cleveland. “We know that marijuana can impair memory and concentration in adolescents, as well as interfere with learning, motor control, coordination and judgment. We also know that regular use is linked to psychological problems, issues with lung health and a higher likelihood of drug dependence in adulthood.”

While 17 states have legalized children's medical use of the marijuana compound cannabidiol, experts have expressed concern about access to it by other children in recent years. Nationwide, marijuana exposure among children under age 5 increased 147 percent from 2006 to 2013, according to a June study from the Columbus hospital.

Some Ohioans may be worried about ending up in a similar situation as Colorado. There, the number of children coming into the largest pediatric emergency room nearly doubled from 2013 to 2014 when the state began allowing the commercial sale of recreational marijuana. Fourteen children under the age of 10 were admitted for eating marijuana, and seven of them required intensive care, Al Jazeera reported. In response, Gov. John Hickenlooper signed a law requiring the state to come up with rules that make edibles easily identifiable both in and out of their packages.