WIMAUMA — Antonio "Marro" Navarrete was 21, in love for the first time and soon to become a dad. He wanted to find a home for his family before the baby arrived in October. The new job he started June 26, earning $12 an hour as a contracted maintenance worker with Brace Industrial Group, made that seem possible.

But on his fourth day at work, Navarrete left his mother a voice mail that will haunt her for the rest of her life.

"Mom help me. Mom I'm burning. Call the cops."

TIMES INVESTIGATION: Tampa Electric records more deaths than any utility in Florida

Navarrete cried out over the phone connection as a lava-like material called slag scorched his skin. He was cleaning equipment at Tampa Electric Co.'s Big Bend Power Station June 29 when a slag tank suddenly erupted, instantly killing two and severely burning four others as they struggled to escape.

"Then you can just hear the 'shhh' of the steam from the slag and the last thing, he just yells, 'Mom' so loud," said his sister Hilda Ramirez, 28. "He was just yelling for her help."

Navarrete, who died Wednesday of his injuries, had been one of the workers taken to Tampa General Hospital. Another Brace contractor, 56-year-old Armando J. Perez, is still hospitalized along with two contractors from Gaffin Industrial Services who are related by marriage: Gary Marine Jr., 32, and Frank Lee Jones, 55.

Doctors told Ramirez all three of the survivors are in medically induced comas, she said, leaving their families with the unanswered question of how such a tragedy could have occurred.

"Before he started they showed him training videos of what could happen and how you are supposed to react and things like that, but in this case there was no way for him, or any of them, to get out," she said. "Once it hit them it was too late."

Navarrete was a skillful mechanic, his sister said, but had told her his new job would require little more than "riding around in a go cart, picking up trash." His family said they have yet to speak with any Tampa Electric employees about what went wrong that day. Instead they string together accounts from first responders and the things they hear from other families in hospital hallways.

Tampa Electric and two federal safety investigators have launched an inquiry that could last six months. Until that investigation is complete, it would be "inappropriate" for Tampa Electric officials to comment on the details of that day, the company said Friday in a statement sent to the Tampa Bay Times.

"We are currently working on a way for team members and members of the community to make contributions in support of all affected by this incident," the statement said. "All workers affected by this incident have been offered free counseling and support."

In a press conference, president and CEO of Tampa Electric Gordon Gillette said the deadly accident occurred as the men tried to unplug a blockage in a slag tank. Molten slag can reach temperatures of more than 1,000 degrees and is a byproduct created when coal is burned for electricity. Chunks fall into cooling tanks filled with water and the remnants, which are black and glasslike, are recycled and used in sand blasting and roofing.

Gillette said removing the blockage is part of routine maintenance. That makes Hilda Ramirez worry someone else could meet her brother's fate.

"He wanted me to go with him to his job and I told him, 'Don't go there, it's too dangerous,' but he wouldn't listen to me," she said. "He kept saying it was the easiest job and he would make lots of money for the baby and his family, and now look at all that's happened. I could have been working with him there too."

When he graduated from Earl J. Lennard High School last year, Navarrete planned to become an auto mechanic.

As a child he would break apart his toy cars to convert them into low-riders and draw pictures of his dream car with modifications like over-the-top engines or speakers. Marro loved tacos, the Pittsburgh Steelers and spending time with his parents and three sisters. He was shy but kind, his sister said. He had such a perfect smile that his orthodontist used him in an ad still posted around Brandon three years later.

When he did take time for himself it was to tinker with "Casper," the white, low-rider Chevy pickup truck he had outfitted with rims, lights and speakers so large that passengers in the back seat had to crouch forward.

On the dashboard he kept a photo of Daisy Martinez, the mother of his child and the only woman other than his mother he had ever loved, his sister said. Last year, Martinez caught his eye and silently smiled at him during a car club event in Wimauma. Six months later, she moved in with him and his parents to start their new family.

His sister-in-law, Delfina Ramirez, 35, said Marro didn't mind her jokes about squeezing a baby carrier next to his truck's back seat speakers. He could hardly wait for the baby to arrive in October. Conversations around the breakfast table on his first day at the new job were all about plans for the baby. The day after the accident, Martinez was scheduled to have an ultrasound that would reveal whether they would have a little boy or girl.

The now-single mother has yet to reschedule the appointment, Delfina Ramirez said.

"Everybody has accidents. You could die in a car crash. But him, he was such a good kid, why did he have to go like that?" she said. "We just have so many unanswered questions."

Contact Anastasia Dawson at adawson@tampabay.com or (813) 226-3377. Follow @adawsonwrites.