More than 1,000 gallons of mineral oil has been spilled near the BGE substation on Waugh Chapel Road, as firefighters continue to try and extinguish a fire that has simmered for nearly 48 hours. 

Maryland Department of the Environment spokeswoman Dawn Stoltzfus said the oil, which is non-toxic, has has not caused any problems for wildlife and does not pose a threat to drinking water. The spill has covered an area of about one square mile. 

Firefighters remained on the scene at the BGE substation Friday to cool a tank holding more than 40,000 gallons of mineral oil. The oil is located near a transformer that erupted in flames on Wednesday afternoon. 

The fire is contained, officials said, but crews remain on the scene to cool the oil tank and prevent flare-ups. Firefighters have been careful to avoid putting too much water on the fire, out of fear that the mineral oil would spill out onto the ground and create environmental hazard. 

Fire officials said they will often let flammable materials such as oil simply burn themselves out, provided there is no threat of injury. But they said that in this instance, they must work to put the fire out because there is concern that an ongoing fire will cause the vessel holding the oil to collapse.  

Stoltzfus said BGE will be responsible for the cleanup of the oil. MDE's emergency response team was on site, along with workers from its oil control division. 

BGE spokeswoman Linda Foy said the spill has been contained and that crews will be on site round-the-clock to ensure no further spillage occurs. She said the cause of the fire and the failure  of the transformer is still unknown, but will be investigated. 

At its peak, the fire attracted more than 70 firefighters and forced the closure of a portion of Waugh Chapel Road. The fire is contained and has not caused any injuries. Waugh Chapel Road is now open to traffic, but cars are being directed around fire crews set up on the road.

"If you looked at it you wouldn't know it was on fire," said Anne Arundel County Fire Department spokesman Chief Michael Cox. "Our main objective now is to make sure that vessel stays cool so that it doesn't reignite."

Cox compared the situation to a deep fryer in a restaurant.

"You know that even after you turn it off, that oil stays hot," he said.

The situation has been made difficult by the lack of fire hydrants at the BGE substation itself. Fire engines have been parked by hydrants on Waugh Chapel Road and long hoses have been stretched to provide water to douse the flames.

Stephanie Burke contributed to this report.