A body of a woman was found in a portable toilet that caught fire and exploded early Saturday, Sept. 28, at a construction site in north Florida, according to authorities.

The St. Johns County Sheriff’s Office wrote on Facebook that authorities responded to the home on North Horseshoe Road in St. Augustine after a report of a porta-potty fire inside a portable toilet. They discovered human remains inside.

“Regarding today’s discovery of human remains contained within a portable toilet, detectives believe the decedent is a white female,” the sheriff’s office said. “At this time, we have not received any missing persons reports that may coincide with this incident.”

Neighbors said they heard a loud explosion around 7 a.m. Saturday in their neighborhood, according to WFOX.

“I just was sitting, watching TV and heard a loud explosion,” one neighbor told the newspaper.

Another said that investigators had to put on hazmat suits as they investigated the area, sifting through dirt and other areas of the construction site for hours.

“The portalet blew up so I mean there’s nothing left, at all,” neighbor Jan Long said.

The sheriff’s office said officials were not immediately able to identify the woman due to the severity of her burns, according to the Florida Times-Union

Sheriff’s office spokesman Chuck Mulligan said the agency has no reports of missing persons. He also says in 32 years of law enforcement work he has never heard of such a fire before.

Mulligan said Sheriff’s Office detectives, along with the Medical Examiner’s Office and State Fire Marshal’s Office investigators, are investigating the death.

The cause of death is not clear, Mulligan added. It remains an undetermined death investigation, pending autopsy findings, and additional background information.