MADISON, Wis. — A marijuana extract used to treat seizures could become legal in Wisconsin after one of the Republican senators who initially opposed the idea signaled her support Thursday for a compromise plan.

Parents of children who suffer seizures have been pushing for legislation that would allow them to use cannibidoil oil, commonly known as CBD oil, to ease the symptoms. Lawmakers voted in 2014 to allow the possession of CBD oil only if dispensed by a physician as part of a medical trial, but there's currently nowhere to get it in Wisconsin and it's illegal to transport it across state lines.

The Assembly passed a bill last session to legalize possession but it died in the Senate after three Republicans — including Leah Vukmir of Brookfield — derailed it amid concerns it would open the door to a larger marijuana legalization effort. Vukmir's spokeswoman, Jessica Ward, said Thursday that Vukmir will support a revised bill.

Sen. Van Wanggaard, who is sponsoring a new measure, expects to introduce the bill later this month. Wanggaard believes there are enough votes to pass, his spokesman, Scott Kelly, said.

Under the proposal, parents who want CBD oil for their children will be able to get a doctor's certification that allows them to legally possess it in Wisconsin, but they'll still need to bring the oil in from outside of the state, Kelly said. Importation would remain illegal under federal law, but Kelly said most state borders are not monitored.

"Unless you have the federal police stopping you on the highway, you're not going to be prosecuted for having it if you comply with the rest of the law," he said.

Assembly Speaker Robin Vos said ensuring access to CBD oil is a priority and that the Assembly planned to pass something in February.

"I don't want to just have another situation where we pass the bill and then it dies," he said Thursday. "We want to help any child who has a problem have another potential treatment."

Sen. Duey Stroebel, another Republican senator who opposed the measure last year, declined to comment on whether his position has changed. The third, Sen. Mary Lazich, did not seek re-election last year; Republican Sen. Dave Craig, of Big Bend, now represents her former district.

The federal Drug Enforcement Administration last month recognized marijuana extract as a separate substance from marijuana and THC, though still classifies all forms as prohibited drugs. This change primarily stemmed from an "over-abundance" of research interest in CBD from the scientific and medical community, according to DEA spokesman Russ Baer.

Kelly said Wanggaard is still determining if the DEA's action necessitated any changes in his bill's language.

CBD oil is low in tetrahydrocannibol, the component of marijuana that causes a high. Fifteen states including Wisconsin have laws permitting some use of marijuana derivatives with low levels of THC for medicinal purposes, but only one, Missouri, has a law that is "workable," according to the Marijuana Policy Project.