HOUSTON — State data indicates many prison units in Texas are understaffed as the state struggles to retain prison guards, with a nearly 30 percent statewide turnover rate last year.

Department vacancy rates edged past 12 percent in the last fiscal year, with more than 3,200 jobs unfilled, the Houston Chronicle reported .

Data from the Texas State Auditor's Office show a 28 percent turnover rate in the state's roughly 26,000 officers at the Texas Department of Criminal Justice last year. The rate exceeded 40 percent in some places. The department had a 23 percent turnover rate a year earlier.

"A lot of these guys don't want to work in a prison," said Lance Lowry, a spokesman for the Texas Correctional Employees union. "There's other job opportunities opening up in rural Texas."

Some experts said officers are leaving for better-paying jobs in oil and gas, or in areas of economic growth.

"When the economy is doing well and growing is typically when we see correctional officers leave for better-paying jobs," said Jason Clark, spokesman for the department. "The more rural areas tend to be more challenging, particularly in South Texas when we've seen an uptick in oil and gas jobs being offered."

Officers have warned that the presence of so many new prison staffers due to high turnover raises safety concerns.

"When you lose 20-some percent of your employees every year, it's hard," Lowry said.

Experts said low wages contribute to the staffing challenges in prisons. Data show officer pay starts at about $32,000 per year and plateaus at $43,000 after seven years.

"If you want the staff to stay — and having experienced staff is critical for effective prison operations — then the pay has to increase significantly," said Michele Deitch, a senior lecturer at the LBJ School of Public Affairs at the University of Texas at Austin.

To boost the workforce, the Criminal Justice Department started offering daily pre-employment tests, accelerated pay schedules for some workers, more part-time jobs and some job fairs. The department has also begun offering $4,000 recruitment bonuses at 25 units particularly hard-hit by staffing issues.