LAS VEGAS — The American Civil Liberties Union filed a class-action suit against the governor of Nevada and other state officials yesterday, alleging that they have failed to rectify “a pervasive pattern of grossly inadequate medical care” at the state’s maximum security prison in Ely.

“These deprivations are so extreme that they subject all the men confined there to constant significant risk of serious injury, medical harm [and] premature death,” according to the suit filed in federal court in Reno by ACLU lawyers from Washington, D.C., and Nevada.

In December, a Los Angeles Times investigation described how prisoners at Ely had been denied care for heart problems, diabetes, and other serious medical conditions. Last year, a nurse at the facility was fired after complaining about substandard care, which she said led to one inmate needlessly dying of gangrene.

At the time, the ACLU submitted to prison officials a scathing report about inadequate medical care at the facility written by Dr. William Noel of Boise, Idaho. Dr. Noel, who had reviewed medical records of 35 inmates, concluded that the conditions at Ely amounted to “the grossest possible medical malpractice, and the most shocking and callous disregard for human life and human suffering that I have ever encountered in my 35 years of practice.”

A spokesman for the Nevada Department of Corrections, Greg Smith, said prison officials had been attempting to respond to the ACLU’s concerns. “Frankly, we’re shocked by this development,” Mr. Smith said. Nonetheless, he said, prison officials believe that medical care at Ely is “more than adequate.”