Yet another US state is turning to unconventional drugs in order to carry out lethal injections. Ohio prison officials announced this week that they plan to execute Ronald Philips, convicted of raping and killing a three-year-old girl, with a combination of two drugs never before used in an execution.

Officials made the decision after determining that they couldn't secure adequate supply of mainstay execution drug pentobarbital. The state ran out of pentobarbital last month, and getting more is a difficult task: the drug's Danish manufacturer in 2011 banned the export of pentobarbital for use in executions, and loosely regulated "compounding pharmacies" tend to shy away from producing drugs for use in lethal injections.

Lethal injection isn't foolproof

It's unclear whether the drug cocktail — which consists of a sedative and a painkiller — carries risks. But lethal injection isn't foolproof: an untested drug combination means that experts aren't necessarily sure how long death will take, whether the injection will be accompanied by marked suffering, or whether the injection might not wind up yielding fatality. "The death penalty is still constitutional, so some method will be allowed," Richard Dieter, executive director of the Death Penalty Information Center, told The Verge earlier this year. "You don't have to remove all risk. What you do have to do is strive to have the most humane, least torturous method as possible of carrying out this brutal task."

And Ohio isn't the only state scrambling to fill its coffers with lethal injection alternatives. Three death-row inmates in Texas recently (and unsuccessfully) requested a stay of execution so that the state — which ran out of its standard lethal injection drug — could test its new execution cocktail prior to using it. In Missouri, state governor Jay Nixon recently halted an execution after the European Union objected to propofol — a drug the EU exports — being used for the procedure.