Eight death row inmates are asking an Arkansas judge to stop their executions, arguing that the state's refusal to reveal where it gets execution drugs is unconstitutional.
The argument, made in a court filing late Monday, is similar to arguments unsuccessfully used by death-row inmates in other states.
But the filing argues that Arkansas new secrecy law violates a previous settlement with the state that ensured inmates would be given the information.
Attorney Jeff Rosenzweig also says the drug midazolam cannot sufficiently mask "serious pain and suffering." The Supreme Court upheld the drug's use in executions in June.
Arkansas is scheduled to resume executions Oct. 21, after a 10-year delay.
The Associated Press this month identified likely sources of Arkansas' execution drugs as three companies that object to their drugs being used in executions.