It is legal in the US to utilize solitary confinement methods that are implemented 24 hours a day. [1] There are facilities without windows and some keep the lights on all day and night in their solitary confinement units. [2]

In a recent story, D3f4ult discussed that this happened to him for a year and he was given 24/7 isolation for one year. [2]

[1]: https://solitarywatch.org/facts/faq/ [2]: https://journalistsresource.org/home/solitary-confinement-re... [3]: https://darknetdiaries.com/transcript/139/