Three inmates at Colorado State Penitentiary have sued the state Department of Corrections in federal district court, claiming that a tiny, indoor exercise room violates their constitutional rights.

The class-action lawsuit was filed Tuesday on behalf of Ryan Decoteau, Anthony Gomez and Dominic Duran by student lawyers at the University of Denver.

DOC spokesman Roger Hudson said he has not had a chance to review the lawsuit and could not comment.

The lawsuit says more than 500 inmates in solitary confinement at the Cañon City prison have been denied their Eighth Amendment rights, which prohibit cruel and unusual punishment.

“Except when immediately adjacent to the small open grate, inmates cannot feel the wind; they cannot feel the sun on their face; they cannot feel the rain or the snow,” the suit says. “This claustrophobic room contains only a pull-up bar, and there is no opportunity for inmates to run, except in a small circle.”

The lawsuit says inmates must spend 23 hours a day in cells that measure approximately 80 square feet and are allowed to exercise in a cell that is only 90 square feet.

Except for medical and legal visits, inmates in “administrative segregation” are allowed to leave their cells only when they are taken to the shower or into another cell called a recreation room, the suit says.

The DOC moved death-row inmates from the Cañon City prison to Sterling Correctional Facility in 2011 to settle a federal lawsuit originally filed by Chuck E. Cheese killer Nathan Dunlap, in which he complained about the exercise rooms.

Former DOC executive director Tom Clements commissioned a study by outside experts in October 2011 that concluded the “denial of outdoor exercise at CSP violated correctional standards and that this practice is extreme and unlike the operation of any other facility in the United States,” the lawsuit says.

Decoteau, 30, Gomez, 28, and Duran, 29, have each experienced mental and physical problems based on incarceration at CSP of as much as 46 months, the lawsuit says.

Kirk Mitchell: 303-954-1206, kmitchell@denverpost.com or twitter.com/kmitchelldp