OKLAHOMA CITY — Two Oklahoma death row inmates sued state corrections officials Wednesday for details about the drugs that will be used to execute them, including their source.

Under state law, no one may disclose who provides Oklahoma with the three drugs it uses in executions, in order to protect the suppliers from potential reprisal. But lawyers for Charles Warner and Clayton Lockett fear the men could suffer severe pain if Oklahoma is allowed to maintain a “veil of secrecy.”

“Plaintiffs have no means to determine the purity of the drug which may be used to execute them, and whether that drug is contaminated with either particulate foreign matter or a microbial biohazard that could lead to a severe allergic reaction upon injection,” the lawyers wrote in their state court lawsuit.

Lockett is scheduled to be executed March 20 for the 1999 shooting death of a 19-year-old Perry woman. Warner is set to be executed on March 27 for the 1997 death of his girlfriend’s 11-month-old daughter. The men seek a restraining order that would halt their executions.