Five inmates on Pennsylvania's death row want a state court to throw out a plan to use a three-drug mixture to execute them.
The challenge to the state's execution protocol will be heard Wednesday in Commonwealth Court in Harrisburg.
The Department of Corrections wants the court to throw out the lawsuit, which claims state officials didn't have legal authority to establish the current procedures in 2012.
If the court sides with the inmates, the case will continue and could result in a trial.
Pennsylvania has executed only three people since the death penalty was reinstated in 1976, the most recent in 1999.
Terrance Williams is one of the five inmates. The state Supreme Court is considering whether Gov. Tom Wolf acted legally last month when he issued Williams a reprieve.