Sewell's family says she called supervisors repeatedly to complain about the fumes before being overcome.
"We can't get her back. That's something we can't get back," said Sewell's daughter, Sherese Brown. "You only get one mother. So that's what really hurts me about the situation."
The family says Sewell was driving the bus last week when she became violently ill, unable to breathe and vomiting. She ultimately died.
"It's the fumes of the bus that killed her," said Joann's husband, Canute Sewell.
Sewell's family says she alerted the Wolfline dispatch office to the fumes coming from a faulty bus but no action was taken.
"You see her that morning, expecting to see her later," said Brown. "This was something that could've been avoided."
Sewell had diabetes, asthma and high blood pressure. However, her family says no autopsy was done. A death certificate shows Sewell died from oxygen deprivation and cardiac arrest.
A spokesperson for the contractor that operates the Wolfline bus system, Cincinnati-based First Transit, says managers are at NC State investigating what happened. The spokesperson told ABC11 that he didn't have records available to determine if Sewell did in fact complain about fumes.
A spokesperson for NC State issued this statement: "The University is not planning to do an investigation into the contractor, First Transit. It is the contractor's responsibility to ensure the matter is handled appropriately, and we believe that the contractor is acting in good faith."
Meanwhile, Sewell's family says they want the responsible supervisor to be fired and for the state to do more to investigate her death.