They say Nathaniel Moody was behind the wheel of the tanker truck when it crashed around 6 a.m. Sunday in the Tacony section of the city.
While his death hasn't been officially confirmed, family members believe human remains found at the scene are those of their loved one.
They say Moody worked for TK Transport in Pennsauken, New Jersey. They say he was an experienced truck driver.
His apparent death has been a devastating blow.
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"He was awesome. He was awesome," said his cousin, Isaac Moody, while fighting back tears.
Isaac Moody says his cousin was his best friend.
"I wasn't expecting this. Nobody was expecting this," said Isaac Moody.
He said the family was told by Pennsylvania State Police that a final identification of the remains in the I-95 wreckage will be done through dental records.
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The family had hoped Nathaniel had escaped and would turn up at a local hospital. It never happened.
Nathaniel Moody leaves behind his longtime girlfriend and a 7-year-old daughter, who was the center of his world.
"I don't know what I'm going to say to her when she says 'Big Cuz, do you see my daddy? Do you know where my daddy is at? Can you find my daddy?'" Isaac said. "I don't know what I am going to say to her."
Isaac Moody, a truck driver himself, says his cousin was a very experienced driver who worked overnight hours.
He says Nathaniel knew the dangers of driving and enjoyed working for TK Transport.
"There is so much that can go wrong with a fuel tanker. If you don't have this valve closed right, if this pressure is not right over there. Nate was very careful with that stuff," Moody said.
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What went wrong is still under investigation.
The family will wait for answers but the grieving has already begun.
"I am kind of baffled. I am trying to not cry because I don't know what happened. I don't know what happened."
We reached out to TK Transport and its parent company, Penn Tank Lines. The company had no comment.