DURHAM, N.C. — Saturday marks two years since the deadly explosion in downtown Durham. A three-month-long investigation revealed it was caused by a gas line that was ruptured during underground drilling. Two people died and dozens were injured.

"We had multiple buildings explode. We had people trapped. We had to run evacuations and it was in the downtown, one of the hardest places for us to actually operate," Durham Fire Chief Robert Zoldos says.

Many in the community, including first responders, are still carrying the pain from that day. The city’s fire chief says some may carry those feelings for the rest of their lives.

Zoldos was on the job for less than six months when the fatal gas explosion happened downtown.

"What it did is show the resolve. 'Bull City Strong' is a saying, but I think you definitely saw your fire department rise to that challenge that day," he says.

Now, two years later, the chief says many of the men and women who responded that day are still healing.

"It’s something that’s a very big deal to us. Our physical injuries have healed, but we know the behavioral health part is going to go on for a while," Zoldos says.

He believes the community may not even realize the pain still felt today.

"I don’t think they understand how serious it is, and how much it means to each responder because they gave a little bit of themselves that day, and they are still going to carry those memories. They are still going to carry that stress, and as much as we do to mitigate it, it’s still going to be something they live with forever," Zoldos says.

Zoldos says fortunately a day like April 10, 2019, doesn’t happen often, but first responders face tragedies on a daily basis, which is why the department continues to prioritize mental health. The department has a behavioral health officer on staff and trains officers to recognize things like early signs of depression.

"We want to continue to monitor and make sure they have the resources, which they do, to take care of them as they move forward in their career," Zoldos says.

Zoldos also says the department is working on getting approval for a tool that would help it more actively detect stress levels of its employees, but he can’t share all of those details yet.