The ACLU of Eastern Missouri says it has learned that the state is running out of its supply of one of the three drugs used in executions.

The ACLU says the state has 50 units of sodium thiopental, but it expires March 1.

The state is preparing for the execution of Richard Clay next week.

Tony Rothert, legal director for the ACLU of Eastern Missouri, says because of the dwindling supply, the Missouri Department of Corrections chose to not use the drug during it most recent execution rehearsal.

"What makes the death penalty constitutional according to the Supreme Court is that there is adequate training and there's a practice process in effect to make sure the executions are done in a way that is not cruel and unusual," Rothert said.

The sole U.S. manufacturer of the anesthetic sodium thiopental is not currently producing the drug.

The Missouri Department of Corrections did not return calls from St. Louis Public Radio, but have told the Associated Press in recent days that the state has an adequate supply for Clay's execution.

Send questions and comments about this story to feedback@stlpublicradio.org.