A maintenance worker who was critically injured when a boiler exploded at a Philadelphia public school in January died Wednesday, union officials said.

Christopher Trakimas, 62, a facility mechanic, was bringing online a boiler that had been shut down for a year at Franklin S. Edmonds Elementary School when it blew up Jan. 13.

"Chris has been in the hospital for five months fighting to overcome the injuries he sustained," an official of his union, Ernie Bennett, posted on Facebook.

"He remained in a doctor-induced coma with third-degree burns on his lower body. While his burns were healing, his body could not sustain," said Bennett, assistant area leader for SEIU 32BJ, which represents Philadelphia School District blue-collar workers.

Superintendent William R. Hite Jr. said he was "deeply saddened" by Trakimas' death.

Trakimas was a 25-year district employee who was "committed to the students and families of Philadelphia, and we owe him a tremendous debt of gratitude for his service," Hite said.

Gabe Morgan, state director for the union, said, "What happened with Chris has been an incredible tragedy."

In April, officials announced that all functioning boilers in city schools had been inspected.

Of the 542 boilers, 58 percent needed minor repairs. Eleven were taken off line for significant repairs. All repairs would be done before the next heating season, officials said.

A forensic engineer was still trying to determine the cause of the explosion at Edmonds, on Thouron Avenue near Gorgas Lane in Stenton. The work on the boiler involved gas and water lines, and the use of fire irons. The boiler had passed an inspection in 2015.

Late Wednesday night, the Trakimas family's lawyer, Colin Burke, said that no lawsuit has been filed, but the firm was "actively investigating this matter."

And the family issued a statement that read:

"We are heartbroken over the loss of our loving husband, father, and grandfather.

"We appreciate all of the prayers and support during this difficult time."