Renewable Energy Group expects to have its Geismar biorefinery, closed following a Sept. 3 explosion, back online by the end of January.

The explosion, the second in six months, injured four workers. An April blast injured two. Both explosions involved equipment that had undergone maintenance and was being restarted.

“The structural damage from the September fire was far less than the April incident. We continue to have great confidence in the technology and facility. Our current estimate is that our team will have the plant back online by the end of January,” President and Chief Executive Officer Daniel J. Oh said.

Oh’s statement was part of the company’s third-quarter earnings guidance. The company expects a loss of $9 million to $15 million.

Louisiana State Police and the U.S. Occupational Safety and Health Administration opened investigations into the second fire. Trooper Bryan Lee said Wednesday that State Police are still investigating. An OSHA spokesman said Wednesday he was checking on the status of that investigation.