Method Comparison
Nitrogen hypoxia is the longest execution the United States has ever used.
Every U.S. execution method, ranked by how long the condemned person remains visibly conscious and in distress after the procedure begins. Every figure has a source, listed below the chart. Verify anything.
Duration of visible conscious distress
Approximate minutes- Firing squad~15 sec
Rapid loss of consciousness from cardiac disruption.
- Hanging (long drop)~1 min
Cervical fracture; unconsciousness within seconds when done correctly.
- Electric chair~2 min
Multiple current cycles; unconsciousness typically within seconds.
- Lethal injection~7 min
Highly variable; botched cases have run 30+ minutes.
- Gas chamber (HCN)~10 min
Historic method; visible convulsions timed at 8–18 minutes.
- Nitrogen hypoxia21 min
Anthony Boyd, Alabama, October 2025 — the longest visible distress of any U.S. nitrogen execution on record.
Range across the 8 U.S. nitrogen executions: ~6 min (Alan Miller, Sept 2024) → 21 min (Anthony Boyd, Oct 2025).
Verify the data
Sources & resources.
Every number on the chart traces back to a public source — eyewitness reporting, federal court findings, DPIC's method tallies, and peer-reviewed historical studies.
- 01Associated Press · Jan 25, 2024
'It was horrific': Reporter describes Kenneth Smith's nitrogen execution
Supports: Nitrogen — Kenneth Smith timing and thrashing (~22 min).
Read source → - 02AL.com (Ivana Hrynkiw) · Oct 23, 2025
Alabama executes Anthony Boyd — witnesses describe extended distress
Supports: Nitrogen — Anthony Boyd, ~21 min of visible conscious distress (headline figure).
Read source → - 03AP News · Sept 26, 2024
Alabama executes Alan Miller by nitrogen — second in U.S. history
Supports: Nitrogen — Alan Miller (~6 min visible distress, low end of the range).
Read source → - 04Death Penalty Information Center
Executions by Method (running tally + eyewitness records)
Supports: Historical baseline for firing squad, hanging, electric chair, lethal injection, gas chamber.
Read source → - 05Death Penalty Information Center
Botched Executions
Supports: Documents 30+ minute lethal-injection cases and multi-cycle electrocutions.
Read source → - 06U.S. District Court, M.D. Alabama · 2026
Lee v. Hamm — Permanent Injunction against Alabama's nitrogen protocol
Supports: Judicial finding that nitrogen hypoxia poses a substantial risk of superadded pain relative to firing squad.
Open on this site → - 07Fordham Urban Law Journal
Denno, 'The Firing Squad as the Sole Method of Execution' (2019)
Supports: Firing squad timing (~15 sec to unconsciousness) and comparative botch rates.
Read source → - 08Stanford University Press · 2014
Sarat, 'Gruesome Spectacles: Botched Executions and America's Death Penalty'
Supports: Historical duration studies for electric chair, gas chamber, and lethal injection.
Read source →