LEE COUNTY, S.C. — Monday marked a year since the deadly riot took place inside Lee Correctional Institution, killing seven inmates and injuring 22 others. Since then, the corrections department says they've made safety changes that may help prevent something like that from ever happening again. 

Related: Inmate: 7 Dead, Bodies 'Stacked on Top of Each Other' in South Carolina Prison Riot

Since the day after the riot, South Carolina Department of Corrections director Bryan Stirling has maintained that the main cause of the riot was contraband.

Related: 7 Inmates Killed, 17 Injured Over 'Real Money, Real Territory' at South Carolina Prison

Stirling says they've made improvements at Lee Correctional Institution and other facilities to make them more secure.

“Security, netting, staff, the front gate, programs, things of that nature," said Stirling.

Related: Attackers Were 'Laughing' at Dying Man During Prison Riot, Inmate Says

At this time last year, Lee Correctional Institution had only a 12-foot fence. The netting, which spans 50 feet over the fence, is designed to help prevent contraband from making its way inside the prison.

SCDC director Bryan Stirling says they’ve added other security enhancements as well.

Related: S.C. Department of Corrections adds security enhancements at facilities

“You saw scanners, full-body scanners, like you would see at the airport when you come in,” said Stirling. “We’ve got drone detection technology," he added. "We know that drones will try to fly over the netting to drop contraband. So, if that happens, we’ll be alerted to that.”

Stirling says they have added three newer model cell phone detectors to prevent them from being inside the facility. They’ve also added a new system to jam cell phone signals and filter what’s going in and out of the prison, according to Stirling.

Related: 2 Inmates Injured in SC Prison Riot Sue Agency for Negligence

"The biggest thing we could do for security and for the safety of the staff that works here is to jam cell phones,” explained Stirling. “Cell phone markets in prisons show the cost has gone up significantly. So, that tells me that we’re not seeing and we’re not finding as many cell phones. But, it’s a constant battle.”

The SCDC says they found 7,240 cell phones and accessories in 2016. In 2017, they found 6,318. In 2018, the department says they found 4,695. So far this year, the SCDC says they've found 884 from January 1st until March 31st.

The Department of Corrections says one of the riots last year broke out in Dorm F-5. Stirling believes part of the issue was the lock system in place.

Related: Lee Correctional Inmate, Stabbed 8 Times in Deadly Riot, Files Suit Against Prison System

Since April of 2018, they've swapped out the air locks with electric in five separate dorms across the state, costing nearly $6 million.

"It was not a broken lock. It was a locking system that's quite expensive to replace,” explained Stirling. “Some of the northern states, they would have this. But a lot of the southern states don't have this. It's something we're going to go to the legislature for."

Another battle the department says it faces is having enough correctional officers. Stirling says he's tried to combat low-staffing by raising pay.

"When I first took over, it [salary] was about $27,000 a year. Now it's $34,000 to $35,000 with this new raise. But, we have unlimited overtime. Our average officer last year made almost $40,000 a year," said Stirling.

New this year is a traveling correctional officer team. The team is made of 30 people.

“If an institution is having short staff because of a sick call or something to that effect, we're going to send this team out to supplement that institution around the state."

As for the investigation, Stirling says they have handed over their report to the solicitor and attorney general's office late last week.

Corrections officials identified the seven inmates killed as Eddie Casey Jay Gaskins, Joshua Svwin Jenkins, Cornelius Quantral McClary, Michael Milledge, Damonte Marquez Rivera, Raymond Angelo Scott, and Corey Scott.

Related: What We Know About the 7 Inmates Killed at a S.C. Prison

At this time, no charges have been filed for the deaths of the seven inmates.