Early on the morning of Friday, November 15, an explosion at one of Chevron’s largest oil refineries was followed by several small fires which caused the death of a Cracking II Processing Unit operator named Tonya Graddy, a 49-year-old grandmother.

Later in the day, Chevron Mississippi General Manager Tom Kovar stated that some unknown object detonated inside the unit’s furnace, sparking the fires that killed Graddy. Kovar explained that a dozen operators were outside the furnace at the time of the explosion and that the fires were contained to a small area.

Kovar also told reporters that “the most important thing now is that we keep the refinery running securely and deal with the investigation.” Reportedly, the refinery continued operation when the investigation began. A company statement explained that the area was safe and secure for the Jackson County investigating officials, including 30 firefighters and police officers, many of whom stayed late into the night.

Plans for the refinery’s fiftieth anniversary celebration over the weekend were cancelled in light of Graddy’s tragic death. Graddy is the fifth casualty in the refinery’s history, the last being in 2003 when a construction worker fell from scaffolding.

The Pascagoula facility is the largest wholly owned refinery, employing 1,610 people and processing 330,000 barrels of crude oil each day. The oil is used for gasoline, jet fuel, diesel, and other products.

In 2009, the Pascagoula refinery was cited by the Occupational Safety and Health Administration OSHA) for 11 violations related to the mishandling of hazardous chemicals. Two were dismissed following an informal settlement. Records show that Chevron paid a $19,125 fine. OSHA also fined Chevron $1,625 for bad lighting in the refinery that same year. OSHA was reportedly also on the scene following Friday’s explosion.

Graddy, who was known as “Toni” to her friends, helped manage the flow of crude through the plant. A friend told reporters, “She was just an outgoing and friendly person, someone you would want to be around, someone you would think about. I was just kind of in shock … you always hear of things happening and you never want to hear the worst, especially to someone you know.”