Red Onion State Prison in Wise County is Virginia’s only super-maximum prison. (DAVID CRIGGER/BRISTOL HERALD COURIER)

About four dozen prisoners at Virginia’s only super-maximum prison began a hunger strike Tuesday, demanding an end to what they call poor conditions, ongoing abuse and the practice of solitary confinement.

Attorneys and groups that represent the inmates say their clients resorted to the strike because no changes were made by the state after complaints about the use of isolation were lodged with the prison and the courts.

State officials said in March that they would implement sweeping changes to Red Onion State Prison this year as part of Gov. Robert F. McDonnell’s four-year plan to help prisoners reenter society. But the inmates say changes are not coming quickly enough.

Mac Gaskins, 32, who spent four years of his 14-year sentence in Red Onion before being released last year, said he received inadequate treatment in isolation, including being beaten by guards and bitten by dogs.

Gaskins, who was convicted of armed robbery, said he does not think the state will make the changes. “They are saying that while still abusing prisoners,’’ Gaskins said. “They’ve been saying they would do a better job. They’ve been saying that for years, and they never did it.’’

A coalition of groups, dubbed Solidarity with Virginia Prison Hunger Strikers, sent a letter with 10 demands to McDonnell (R) and U.S. Sens. James Webb and Mark R. Warner (both D-Va.).

McDonnell’s office referred calls to the Virginia Department of Corrections. Red Onion spokesman Larry Traylor declined to comment on the strike, but the department issued a statement.

Red Onion “has always operated constitutionally and protected the Eighth Amendment rights of offenders, and has been nationally accredited by the American Correctional Association,’’ the statement said. “The DOC is continually looking at ways to improve its operations and to enhance management of offenders by applying science as it evolves in the field of corrections.”

The hunger strike comes months after a group of lawmakers visited the remote Southwest Virginia prison and called on officials to curb the use of solitary confinement, especially for the mentally ill.

The prisoners’ demands include an end to indefinite segregation— the word the state uses for isolation — as well as fully cooked meals, monthly haircuts and an outside review of the facility.

State officials have said they plan to appoint a team of experts to examine each prisoner, add more levels of review before inmates are placed in solitary confinement and transfer some inmates to a nearby prison.

Nearly 500 inmates at Red Onion spend 23 hours a day in a cell, don’t shower daily and have limited recreation. Some prisoners, including those with mental illnesses, have been kept in isolation for years, inmates and lawyers say.

Webb’s office declined to comment on Red Onion, but said the retiring senator “has long called for a comprehensive review of the nation’s criminal justice system.’’

Some members of the Virginia General Assembly and human rights groups have asked the U.S. Justice Department to investigate the use of solitary confinement at Red Onion.

Del. Patrick A. Hope (D-Arlington), who calls segregation “torture,” said inmates must think that the changes the state promised will not occur. “They’ve had it, and they want to see some changes,’’ he said.

Red Onion, built on a mountain about 400 miles from Richmond, isolates more inmates than any other facility in the state — nearly 500 of the state’s 1,700. Inmates are kept in isolation for disciplinary problems, such as assaulting other prisoners or having drugs, or for protection, officials said.

As the effects of isolation — on inmate health, public safety and prison budgets — become clear, some states have begun to reconsider solitary confinement. New York, Mississippi and Texas are scaling back the practice under pressure. Virginia is one of 44 states that houses inmates in isolation.