One mechanic was killed and another seriously injured after a large tire exploded at the Port of Los Angeles on Wednesday morning, according to a labor union representative.

Firefighters and paramedics were dispatched to the APL Terminal in San Pedro shortly before 7:25 a.m. after receiving a 911 call regarding an “injury incident,” Los Angeles Fire Department officials said.

When they responded, LAFD personnel discovered one person dead at the scene and another wounded, according to the department.

Greg Mitre, president of the International Longshoreman and Warehouse Union’s Pacific Coast Pensioners, told KTLA the blast occurred while two mechanics were reinflating the tire of a top-handler, a piece of heavy equipment used for moving materials and shipping containers.

The wheels are approximately 5 to 6 feet in diameter.

As the two men worked on the tire, something went wrong and it exploded, instantly killing 58-year-old Jose Santoyo.

Ray Familathe, who is with ILWU Local 13, identified the victim to KTLA.

“I had to deliver the personal message to the deceased man’s family today,” he said. “It was his grandson’s first birthday. So it was a very untimely tragedy.”

Santoyo’s colleague – Pedro Chavarin – suffered severe head injuries and was rushed to Harbor UCLA Medical Center where he was placed in a medically induced coma, according to Familathe.

The two victims had worked together for decades.

Los Angeles City Councilman Joe Buscaino, whose district includes San Pedro, released a statement in the aftermath of the explosion.

“I am heartbroken to hear that this morning we lost one our ILWU brothers in an industrial accident at the Port of Los Angeles while another has been seriously injured,” the statement said in part. “Today is a tragic reminder of the danger that thousands of workers face every day working on our docks.”

The death is the first at the port in about three years, according to Mitre.

“We haven’t lost anyone in three years, but today is a sad day for the ILWU, it’s a sad day on the waterfront,” he said. “We work in a dangerous environment, there’s a lot of cargo here – upwards of 18 million containers a year.”

The death also happened to take place the same day as the annual First Blood Ceremony, which honors workers who have died on the job in the past year. The ceremony was held at the docks early in the afternoon.

Dockworkers on the pier were released early for the day because of emotional distress.

Authorities did not provide any additional information about the incident which is being investigated by a number of agencies including Cal/OSHA and the Los Angeles Port Police.

KTLA’s Steve Bien and Morgan Ball contributed to this report.

CORRECTION: A previous version of this story included an incorrect spelling of one of the victims’ names, provided by the union. The story has been updated.