Against a backdrop of growing scrutiny over security, inmate health care and overcrowding, state prison officials offered a rare inside peek into a maximum-security prison facility on Friday.

Reporters were taken on a tour of the newly constructed 500-bed expansion of the Rast Unit at the Lewis Prison Complex in Buckeye, which was built to address the state’s swelling prison population.

“We’ve been using temporary beds for 30 years,” Arizona Department of Corrections Director Charles Ryan said.

Ryan said about 300 inmates currently in Corrections’ Eyman prison in Florence will be transferred to the new facility beginning next month. The remainder of the beds will be filled with new arrivals or inmates transferred from other prisons.

The open beds left at Eyman will be filled with inmates from other prisons determined to be “predatory,” Ryan said.

The new 500-bed unit at the Lewis Prison Complex is equipped with cells that have high-security doors offering greater visibility, Americans with Disabilities Act compliant cells and showers and touch-screen operated security features in the control rooms. The total construction cost was $50 million.

But even that added capacity does not address the more acute problem of population growth.

It’s in the medium security levels where the most new beds are needed, Ryan said.

“The level of overcrowding occurs in dormitory,” Ryan said, explaining that lower-security level inmates often are housed in such settings.

In those dormitory units, the department has for years resorted to installing bunk beds as a way to address the ever-expanding inmate population.

In fact, even before the addition of 500 beds at Lewis, ADOC had some 200 surplus maximum-security beds.

Ryan said it wouldn’t take long to fill those beds though, as the department estimates the state’s inmate population is expected to grow by nearly 1,000 people each year for the next two years.

As of August, more than 41,000 inmates were incarcerated in ADOC prisons, or roughly 0.6 percent of Arizona’s total population.

While the state’s population has more than doubled since 1980, going from 2.7 million to 6.6 million, the prison population has grown more than 11 fold. In 1980, the state had 3,600 prisoners.

The Arizona Department of Corrections has a $1.1 billion budget for the current fiscal year.

The new facility has drawn some criticism.

“You were probably looking at the most colossal waste of taxpayer money,” said Caroline Isaacs, program director at the Tucson office of the American Friends Service Committee.

The group studies prison conditions and other issues in the penal system.

Isaacs said the expansion was unneeded, considering the department already has a surplus of maximum-security beds.

She suggested Arizona adopt sentencing reforms and other measures to address prison overcrowding and crime issues.

“Most states have done some kind of tinkering with their sentencing practices,” Isaacs said.

The prolonged execution of murderer Joseph Wood in July also focused attention on the department. The execution took nearly two hours to complete as corrections officials repeatedly dosed the condemned man with lethal drugs.

The Arizona Daily Star has signed onto a lawsuit seeking to force the state to reveal information about the drugs, including their source.

An investigation and report should be finished this month.

State prisons also have been under scrutiny for the quality of medical care provided to inmates. A group of inmates earlier this year filed a lawsuit — which a judge later granted class-action status — incorporating all of the inmates in ADOC-run facilities, saying medical, mental health and dental care was lacking.

Plaintiffs claim the Corrections Department and its contracted health-care provider routinely delayed or denied medical care to inmates.

The average annual cost of medical care for inmates in Arizona was $3,258 in 2011, according to ADOC records, down from an average of $4,500 a year in 2009.

While admitting no fault, the state entered into an agreement with the plaintiffs to improve the quality of care and to reform policies on isolation of inmates, also known as solitary confinement.

Isaacs said the agreement represented a good start.

“We have nowhere to go but up,” she said.

Contact reporter Patrick McNamara at 573-4241 or pmcnamara@tucson.com. On Twitter @pm929