Four death row inmates in Tennessee have asked a federal court to allow them to be executed by firing squad.
The lawsuit was filed on Friday a day after Edmund Zagorski was executed at a Tennessee maximum security prison using the electric chair.
His attorneys argued the method was more humane than lethal injection because it would take a shorter amount of time for Zagorksi to die.
Zagorski's death was the first electrocution the state had conducted since 2007.
Mississippi, Oklahoma and Utah are the only states that allow the use of firing squads in executions.
The last time the method was used in the US was in 2010, when Ronnie Lee Gardner was executed in Utah for the 1984 murder of attorney Michael Burdell during a failed courthouse escape.
A lawyer representing the four Tennessee inmates has said lethal injection is the "default method" of execution, but those on death row can also choose electrocution.
The death row prisoners include David Earl Miller who is scheduled to be executed on 6 December and is the longest-standing death row inmate in the state.
Miller was sentenced to death in 1981 for the rape and murder of mentally handicapped Lee Standifer, 23, in Knoxville.
He will be asked on Tuesday to choose his execution method.
The lawsuit seeks to delay that decision until a federal judge can review the case.
Stephen Kissinger, a federal public defender representing the inmates, said: "There exists one or more feasible and readily-available alternative methods of execution which substantially reduce the constitutionally unacceptable risk of inflicting unnecessary and serious pain created by the use of electrocution to carry out plaintiffs' executions."
The lawsuit adds that the state already has the trained personnel, firearms and space to allow for a firing squad.
It also asks for permission to use other alternatives such as orally administering lethal drugs over using a needle, or using different forms of drugs, if the court disagrees with the suit.
Mr Kissinger wrote: "Because lethal injection is the default method of execution, plaintiffs must elect electrocution in order to avoid a harsher punishment than the punishment provided by law at the time of the crimes."
The lawsuit goes on to argue that if an inmate chooses electrocution, they "may forfeit the right to challenge the constitutionality of electrocution under the Eighth Amendment".
A Department of Correction spokeswoman said it would be "improper" to provide a comment with the lawsuit still pending.
Other inmates listed in the lawsuit include Nicholas Todd Sutton, Stephen Michael West and Terry Lynn King.
Miller, Sutton and West had filed a similar lawsuit earlier this year pushing for alternatives to Tennessee's lethal injection method.
They eventually voluntarily dismissed their case due to other challenges to the state's execution procedures.
Lethal injection has become a controversial execution method in the US after several botched procedures.
More from Tennessee
Oklahoma death row inmate Clayton Lockett, who had been convicted over the kidnap and murder of a 19-year-old, took 45 minutes to die when an intravenous line into his groin fell out.
It was not noticed until 21 minutes after the execution began and all the lethal drugs had been administered.
[contf] [contfnew] 
Sky News
[contfnewc] [contfnewc]
