That difficulty was part of the reason Louisiana lawmakers legalized the use of nitrogen gas and the electric chair as methods for carrying out death sentences last year. At the time, a group of Jewish citizens appealed to lawmakers to reject the use of gassing, saying it evoked the gas chambers used during the Holocaust.

Louisiana has approved a protocol for executions by nitrogen hypoxia, which will allow death sentences to be carried out again after nearly 15 years, Gov. Jeff Landry said Monday.