LAKE CHARLES, LA (From KPLC) -- Eleven fifteen in the morning, Wednesday, February 8, 2017. There was an explosion at the Packaging Corporation of America, DeRidder facility. According to OSHA, the Occupational Safety and Health Administration, three contract workers were climbing down from an elevated pipe rack when what's called a foul condensate tank exploded. The blast hit the employees and tossed their bodies 200 yards, killing all three.

There was a fourth worker in that crew, but Guadalupe Delarosa survived.

"I was ten feet away from the tank and I saw everything that happened. The reason I saw everything that happened, I can't explain it, why I didn't die or got killed. Just an act of God, God had mercy on me, had his hand on me," said Delarosa.

Those killed were Jody Gooch, age 40 of Newton, Texas; William Rolls, age 32 of Mittie; and Sedrick Stallworth of Alabama. Delarosa says Rolls was his good friend. He wants all to know that the crew was professional, safety minded and followed procedures.

"They were top-notch, experienced, seasoned construction workers, welders," said Delarosa.

Delarosa, who served as the watch person for the crew, says when the tank blew it sounded like a bomb went off -- and then.

"When that gulf, that wave of hot water coming out of the tank came at me and I was like in a flood, like in rapids. It washed me out of the unit, I was almost passed out because of the pressure wave that hit me," said Delarosa.

He struggles with survivor guilt.

"Unbelievable. It was like a war zone in there. And I tried to go in there but I couldn't go in there because I couldn't walk," said Delarosa.

"My mind wanted to go, but my body wouldn't help me," he said.

Delarosa was one of seven injured and spent several days hospitalized. He says there are painful physical and mental effects that remain -- especially post-traumatic stress from the event.

"I get on my knees and pray, that's all I can do. Mental anguish a lot, I deal with that a lot," he said.

A year after the horrific accident, several local, state and federal government agencies are still investigating.

The U.S. Chemical Safety Board, based in Washington D.C., sent a team to DeRidder to do an independent probe of the blast. Their goal is to make workplaces safer.

We spoke to board chair Vanessa Allen Sutherland in California, who says they are doing a very thorough investigation into the accident.

"Our team has done a great job so far, finding out that the explosion itself involved a large tank, and when that exploded it flew 370 feet over a six-story building before landing on process equipment and we have uncovered that of course that was caused by hot work that was probably being done under and near the tank before the fire occurred," said Sutherland.

Hot work is welding or cutting activities that could produce a spark or flame. Accidents happen when flammable gas or liquids ignite and explode. The investigation by the board continues yet:

"We believe that the cause was the ongoing hot work repairs right above the tank likely ignited the flammable vapor inside the tank causing an explosion," she said.

Sutherland says deaths and injuries from hot work happen often and they're trying to address it and improve hot work safety:

"Due to the frequency of events we really wanted to uncover why do they happen and what might we learn from this additional incident. Hot work is actually one of our critical safety issues at the Chemical Safety Board. We are focusing our attention and resources on bringing this issue to light, because a targeted effort, we hope, will reduce the continued, recurring events we see literally on an almost on a weekly basis," she said.

Earlier the board produced a video on hot work accidents including a PCA explosion in Wisconsin in 2008 in which three workers were killed.

"Welding sparks ignited flammable hydrogen gas, from an 80-foot tall storage tank," says the narrator on the safety video.

Two years later, the CSB issued seven key lessons to prevent such worker deaths. during hot work in and around tanks.

"Test the area, where hot work is planned and eliminate potential sources of flammables even in equipment that is not directly involved," says the narrator.

We don't yet know if there are similarities between the 2008 PCA accident and the one last year.

Sutherland says the current investigation is in its final stages and should go before the CSB for approval within three months, though she says their recommendations will focus not on who to blame but worker safety.

In addition to the CSB, OSHA has identified five serious violations against PCA, stemming from the incident and attempted to impose $63,375 in penalties. But the website indicates the company is fighting the violations.

At least seven lawsuits have been filed in Beauregard Parish by survivors of those who died and those who were injured, including Delarosa and there are suits in Texas. Delarosa says he especially hopes those who lost loved ones will be compensated.

He urges those who work in potentially dangerous situations to always focus on safety first and remember never take life for granted.

"Tomorrow ain't promised to us," said Delarosa.

We reached out to PCA offices in DeRidder and Chicago for a comment or update, but have not heard back.