Nitrogen Hypoxia as an Execution Method

Nitrogen hypoxia is the newest execution method to move from statute into actual use in the United States. It emerged after years of lethal-injection drug shortages, failed IV placements and litigation over execution protocols. States that adopted the method presented it as an alternative that did not require intravenous access.

What nitrogen hypoxia means

2026 legal landscape

According to the Death Penalty Information Center's current methods overview, five states specifically authorize execution using nitrogen gas: Alabama, Arkansas, Louisiana, Mississippi and Oklahoma. Alabama and Louisiana have issued protocols and are the two states that have actually carried out nitrogen-gas executions.

Why it is controversial

Supporters have described the method as a way to avoid the IV-access failures that plague lethal injection. Critics, defense lawyers and medical experts have challenged claims that the process is predictably painless and have pointed to witness accounts of movement, gasping or prolonged distress in some executions. Litigation has focused on mask design, oxygen leakage, vomiting risk and whether the procedure creates an unconstitutional risk of suffering.

Connection to the botched-execution cluster

Sources

– Death Penalty Information Center — Methods of Execution – Death Penalty Information Center — State-by-State Execution Protocols – Death Penalty Information Center — Authorized Methods by State