Which states have formal execution protocols (not just statutes) for nitrogen hypoxia and what do those protocols disclose?
Executive summary
Two states are known to have issued formal, operational documents describing how nitrogen hypoxia would be carried out: Alabama published a heavily redacted execution protocol that was used in practice and spells out steps such as fitting a mask, monitoring by EKG and timing rules, while Louisiana released a brief summary of its nitrogen hypoxia protocol in 2025 after authorizing the method by statute (Alabama — [1]; Alabama details — [2]; Louisiana summary/release — [3]; p1_s2). Other states — including Oklahoma and Mississippi — have statutory authorization or have considered bills, but, according to available reporting, have not produced a comparable operational protocol made public (Oklahoma/Mississippi authorization noted; lack of protocols reported — [4]; [5]; [3]2).
1. Alabama: the only detailed public protocol (but heavily redacted)
Alabama publicly released a multi‑page “Executions Protocol” for nitrogen hypoxia that the state has defended in court and that was the basis for carrying out the nation’s first known nitrogen‑gas execution; the public version is heavily redacted but nonetheless specifies key operational elements such as using a face mask to deliver pure nitrogen, the condemned person being restrained, EKG monitoring, and a prescribed minimum administration period (at least 15 minutes or five minutes after a flatline, whichever is longer) (publication and redactions described — [1]; mask, restraints and timing language — [2]; [3]0).
2. What Alabama’s protocol discloses about procedure and monitoring
The portions of Alabama’s protocol made public describe placing a mask on the inmate, replacing inhaled oxygen with nitrogen gas, administering the gas from another room with EKG monitoring, and continuing gas flow for a set interval tied to cardiac activity — language the state used to argue the method was humane — while the document also contains redactions that shield technical and security details from public view (mask, replacement of oxygen, administration from another room, EKG/timing rules — [2]; [6]; redactions and state’s characterization — [1]; [3]2).
3. Louisiana: a brief protocol summary surfaced after statute change
In 2025 Louisiana published a brief summary describing execution by nitrogen hypoxia that echoes operational features — placing a mask on the inmate’s face and administering pure nitrogen through it sufficient to cause death — and the state said it would resume executions after a long hiatus using the newly authorized method; reporting frames Louisiana’s document as a summary rather than the multi‑page, operational protocol Alabama produced and notes Louisiana’s legislative authorization preceded the summary (Louisiana summary language and timing — [3]; p1_s2).
4. Statutes vs. protocols: where many states stop at authorization
Several states have statutes authorizing “lethal gas” or the option of nitrogen hypoxia in law, but authorization does not equate to a publicly released, step‑by‑step protocol; Oklahoma first authorized nitrogen hypoxia by statute in 2015 and Mississippi likewise authorized lethal‑gas options, but reporting repeatedly identifies Alabama as, until recently, the sole state to disclose an execution protocol and frames other states as having statutes or bills rather than public protocols (Oklahoma/Mississippi authorization and distinction between statutes and protocols — [4]; [5]; [7]; confirmation that Alabama was the only state with a protocol until Louisiana’s summary — [8]; p1_s9).
5. What the disclosed protocols do not answer and why critics object
Even where states have released documents, critics — including human‑rights experts and medical commentators — stress that redactions and the sparseness of public summaries leave essential questions unanswered (for example, whether sedatives will be used, how leaks or mask seal failures are handled, and the basis for claims that nitrogen hypoxia is painless), and international bodies and advocacy groups have warned that Alabama’s protocol as published omits sedative provisions and could pose serious humanitarian and safety risks (redactions and missing detail criticized — [1]; concerns about lack of sedative and human‑rights alarm — [9]; p1_s4).
6. The near‑term landscape: limited public protocols, contested science and political motives
The empirical record is narrow: Alabama’s redacted operational protocol and Louisiana’s brief summary are the only expressly published state execution documents for nitrogen hypoxia in reporting to date, while other states remain at the statutory or proposal stage; proponents frame the move as a pragmatic response to drug shortages for lethal injection, whereas opponents and some manufacturers warn of secrecy, medical uncertainty and reputational or legal risks that have tamped down wider adoption (Alabama and Louisiana as only protocols published — [8]; [10]; legislative momentum and manufacturer resistance noted — [11]; statutory origins in Oklahoma and Mississippi — [4]; p1_s6).