COLUMBUS, Ohio (AP) - A condemned Ohio killer is suing to stop his March execution, alleging the state's capital punishment policy leaves open the chance an inmate could remain clinically alive after being pronounced dead.

Attorneys for death row prisoner Gregory Lott say inmates also run the risk of experiencing unnecessary pain under the state's current execution system.

The lawsuit filed Thursday in federal court asks a judge to halt Lott's March 19 execution, declare the state's new policy unconstitutional, and determine that Ohio is violating state and federal drug laws by its use of drugs without a prescription.

Lott was sentenced to die for killing 82-year-old John McGrath by setting him on fire in his East Cleveland home in 1986.

Courts halted plans to execute the 51-year-old Lott ten years ago.