Renewable Energy Group workers standing near the source of an April 2 fire at the Geismar biofuel complex reported hearing a noise, possibly a hissing sound, moments before a pump caught fire, broke out into a blaze that took five hours to extinguish and injured two men, a State Police report says.

The report, which troopers released Wednesday, provides a look at the dramatic moments immediately before and after the fire began, and describes the explosions inside the plant and the fireball that rapidly expanded from a leaking pump, sending workers racing to escape its path.

“As I was running to get away from flames, fire engulfed around me. Then I stopped, dropped and rolled on the ground,” said Benjamin J. Richard, 39, of Prairieville, who was burned in the fire.

State Police, who did not cite the company for violations after the fire, have said a bad seal on a pump blew out and sparked the flash fire about 6:30 p.m. April 2.

But the newly released State Police report says the pump in question had undergone regular maintenance. It was being put through startup procedures and was ready to be restarted by Richard and two other workers when it caught fire. Richard could not be reached for comment this week.

Dan Oh, president and CEO of REG, told analysts in a conference call Tuesday the company’s investigation into the fire so far does not point to a problem in the biodiesel production process.

“We believe our production process is well-understood, stable and safe,” Oh said. “We will reaffirm this before operations resume at Geismar.”

In response to the State Police report, Anthony Hulen, REG spokesman, said Thursday the company’s internal investigation is ongoing.

“Any determinations of the actual cause of the fire are still preliminary until all investigations are completed, and we will determine the actual cause and take appropriate measures to prevent similar incidents in the future,” Hulen said.

Oh told analysts that the company’s fire investigation and repair of the plant off La. 30 is expected to last three more months. The company also has moved up the timeline on maintenance planned for the summer and will do it while the facility is down.

REG officials said two employees hurt in the fire are recovering. Brandon Nickens, 57, of Ponchatoula, who was also burned, declined this week to talk about his experience. He did say he and Richard are out of the hospital.

It’s still not clear how much biodiesel burned in the fire or what was emitted into the air, estimates that companies are typically required to provide to the state after a major event like the fire.

Hulen said the company has submitted the estimates to state Department of Environmental Quality officials.

DEQ said Wednesday it is still gathering information.

The U.S. Occupational Safety and Health Administration is probing the fire, too, OSHA’s website says.

The speed of ignition from the flash fire and the expansion of the resulting fireball appeared to have left workers struggling to get clear of the fire, according to accounts provided to State Police.

Richard wrote that the fire came out of the pump seal “before I could grab my radio and let everyone know.”

Jessie Phillips, 61, an operations supervisor who was checking a seal on the pump, told State Police he heard a noise from the seal, followed immediately by a fireball.

“The fireball was expanding rapidly,” Phillips wrote. “I immediately turned and ran east, away from the pump area. At about 50 feet from the pump, I stopped and turned to look at the pump. The fireball was still expanding.”

Nickens, who did not hear a noise but was standing on the other side of the pump from Richard, had to run from the fire once it started and rolled on the ground to put out the flames on his arm.

Nickens had to get up and keep running away because the fireball was continuing to expand, he told State Police.

“When I reached the roadway, I went to my knees to see if I was still on fire. Another operator came up behind me to assist me,” Nickens wrote.

The other worker put Nickens under a safety shower, but both men had to move farther from the blaze again, behind a concrete wall, because of an explosion.

Phillips added he also had to keep moving away from the fire while he told workers to close valves, start putting water on the fire and as he accounted for workers.

Firefighters put out the blaze about 11:30 p.m., State Police said.

Follow David J. Mitchell on Twitter, @NewsieDave.