Yes. It's been approved for capital punishment in the US state of Oklahoma: http://www.newyorker.com/news/news-desk/how-oklahoma-came-to-embrace-the-gas-chambe

Yes. It's been approved for capital punishment in the US state of Oklahoma: http://www.newyorker.com/news/news-desk/how-oklahoma-came-to-embrace-the-gas-chamber http://www.newyorker.com/news/news-desk/how-oklahoma-came-to... Also search for “exit bag”. You’ll find instructional images, as well as an instructional video made for the sick and elderly, about using this technique to commit suicide.