As much as 3,000 gallons of fuel -- believed to be gasoline -- is thought to have leaked in the area of the underground storage tanks at the Marathon gas station located on North Jackson Street, according to Greencastle Fire Chief Bill Newgent, who remained on the scene Wednesday morning.
An unknown amount of that fuel made its way into the city's sanitary sewage system and workers are continuing to deal with the problem.
Greencastle Wastewater Superintendent George Russell explained Tuesday that the fuel appears to have seeped into at least two different underground sewage lines in the area -- one running directly west from the gas station, along Daggy Street and back to the sewage plant on West Columbia Street, with the second running north, from the gas station, to Shadowlawn Avenue and back to the sewage plant.
On Tuesday night, the sewage department sent a camera up the sewer lines near the gas station and could actually see the fuel infiltrating the pipe, Newgent said.
There is some good news coming from the incident.
Russell told the BannerGraphic Wednesday morning that it appears any damage caused by the fuel entering the actual sewage plant is minimal. Officials from the Indiana Department of Environmental Management were at the plant assisting in the monitoring Wednesday morning.
"I think they're happy with what they're seeing at this point," Russell said. "The plant's doing great."
One concern that remains is that some of the fuel may have made its way through the sewage plant and into nearby Big Walnut Creek before it was detected.
"Is there some that hit Big Walnut? Yes. How much? I think it's very minimal," Russell said.
He said environmental officials would continue monitoring that area and would take the necessary action.
So far, investigators have not been able to determine how long the fuel has been leaking from the gas station, however, Newgent said residents living on the north and west sides of town have been reporting a strong gasoline odor in the air since Sunday.
The odor inside the manholes and sewer lines near the gas station became so strong Tuesday afternoon -- testing at 100 percent saturation -- that officials were forced to immediately shut down the gas station and take emergency action. Newgent said the vapors were at their peak for explosive danger Tuesday afternoon.
"At that level, it's in its prime and we need to ventilate the structure, the house or wherever it is," he said.
On Tuesday, large fans were placed over top the manholes in the area in an effort to remove as much of the dangerous fuel vapor as possible.
Fortunately those levels had dropped to safe levels by Wednesday morning. Newgent said tests showed the flammable vapors had dropped to just 4 percent, and he was feeling more at ease about the explosive danger.
On Tuesday, one of the first things officials did was close off the underground storage tanks, which allowed them to stop the flow of fuel through the system. Still workers were struggling to figure out how much fuel had leaked and where it went.
As of Wednesday morning, crews had dug a large trench parallel to the gas station in an effort to stop the remaining fuel from leaching into the nearby sanitary sewer line. The hole measured approximately 60 feet long and 8 to 9 feet deep early Wednesday, but Newgent felt it would have to be enlarged as the investigation continues.
Newgent said the trench serves as a collection point for the fuel which stops it before it reaches the sanitary sewer line. On Wednesday morning, a large tanker truck sat next to the trench and was actively pumping out the fuel.
Workers were having trouble digging the trench because the sides started to collapse, Newgent said. They were waiting to enforce the sides of the trench before moving on. Newgent said the work could go on for quite some time.
All that is really known at this point is that the fuel leaked somewhere between the tanks where the it is stored and where it is pumped to the fueling centers.
Newgent said state environmental officials, who also remained at the scene throughout the night, told him there was several options for dealing with the fuel spill in the coming weeks and possibly months. One of the options, he said, is to completely remove the dirt near the gas station and replace it.
Officials have not had time to gauge the actual size of the contaminated area.
Newgent said he did not know what the mitigation plan would be, at this point, but that more decisions will have to be made at a later time. It is the largest fuel spill, of its type, that Newgent has handled in his career with the fire department.