Scott Thrower, 47, died as a result of injuries he suffered during the explosion on the chemical plant, Louisiana State Police reported.
Zachary Green, 29, a plant operator who had worked at the facility for a few months, died on Thursday shortly after being taken to hospital after the incident.
Local officials reported that five people remained hospitalized in conditions ranging from critical to fair on Friday.
The explosion sent a huge fireball and column of smoke into the air above the building along the Mississippi River, about 60 miles from New Orleans.
Williams Olefins CEO and President Alan Armstrong called the explosion “a tremendous tragedy.”
“A lot of us in this industry have spent much of our careers working to make it safe, so when something like this happens, honestly, it feels like a big failure,” Armstrong told reporters with his voice shaking, shortly before police announced a second person had died.
“Your heart sinks, and it’s just hard to know what to do, you feel pretty helpless,” Armstrong added.
Parent group the Williams Companies Inc operates the plant and holds an 83-percent stake in it.
The cause of the blast is yet to be identified and the company is expected to launch an investigation as soon as all the remaining flammable hydrocarbons in the plant dissipated and it was safe to re-enter, plant manager Larry Bayer said.
Louisiana Governor Bobby Jindal on Thursday vowed to find who is to blame for the tragedy whoever may be at fault.
The company’s injury toll of 100 was higher than the figure of 73 given by Jindal on Thursday, Reuters writes.
Bayer said 839 employees were at work at the moment when the blast took place, a larger-than-normal number because a major expansion was under way.
A small number of workers were performing in 12-hour shifts “to assure the plant is being safely shut down and monitored,” Bayer said, declining to reveal when the chemical plant would reopen because the extent of the damage was still unknown.
The materials that burned in the fire after the explosion were primarily propane and propylene, Bayer said: “We anticipate we will have everything burned off in a day or so.”
The news of the incident comes a few months after another plant explosed in Texas, carring away lives of more than 70 people and injuring hundreds of others.
Firefighters had responded to a call at the West Fertilizer Co on April, 18, before the 8 p.m. blast that rocked West, a town of 2,700 people about 20 miles north of Waco.
A police officer also revealed that a significant area of the plant had been destroyed, and that homes were damaged as far as five blocks away: “Homes have been destroyed. Part of that community is gone.”
Light rain was falling and winds reached the speed of 22 miles per hour on that morning, conditions that became an obstacle for the recovery effort or prompt additional evacuations.
“I’ve never seen anything like this,” McLennan County Sheriff Parnell McNamara said. “It looks like a war zone with all the debris.”