The CT Department of Energy and Environmental Protection (CT-DEEP) has been called in to remediate an oil spill that occurred in December at a Nod Hill Rd. home. As much as 600-800 gallons of oil spilled onto a dirt floor in the basement of a house at 166 Nod Hill Rd., a nine-acre parcel that sits on the edge of the South Norwalk Electric and Water/Second Taxing District reservoir known as Streets Pond.

Close up of property (blue square in main image)

The spill occurred when two, recently-installed 330-gallon heating oil tanks located in the home’s basement collapsed sometime after two fuel deliveries–one to fill the tanks and another to top them off. The collapse caused the tanks’ feeder pipe that connects to the furnace to detach and break, spilling what officials say could be as much as 600 or more gallons of oil into the earth below the house.

“This was actually an unfortunate, complete accident,” reports Ken LeClerc, the emergency response coordinator with CT–DEEP overseeing the response effort. “It’s one of those things that happened. The leg collapsed, there’s nothing that could have been done to prevent it. And that situation, it was just an installation error. I’ve worked for DEEP for 20 years–this is the first time I’ve ever seen it happen.”

The company that installed the tanks was D.R. Charles Environmental Construction, based in Monroe; and the company that provided the oil was Servco Oil in Wilton. According to LeClerc, both companies have been very responsive.

“They both stepped up to the plate. D.R. Charles immediately, from the first day, took responsibility for it. And Servco, which is owned by Santa Fuels, has been onsite–one of the owners has been onsite every day. They’ve hired consultants out of their own pockets to make sure everything possible has been done. They’re both good, reputable companies, that that have done anything DEEP has asked, anything the health department has asked, anything DPH has asked, they were on it immediately.” LeClerc says.


Officials aren’t able to pinpoint exactly when the spill occurred, but they believe it occurred sometime on or around Dec. 20, 2019. The homeowner had passed away recently, and the house was unoccupied. Family members had been readying the house for sale, and the estate had recently removed a 2,000 gallon underground [which, LeClerc notes, had “come out clean” and was intact when it was removed]. The new above ground tanks were installed in the home’s basement as replacements.

The spill was detected a short time after a recent delivery of oil to the home, during a visit by a family member to check the house. “It could’ve had probably up to a three day head start on us,” LeClerc says.

DEEP was notified and has been overseeing monitoring and remediation since then; the Wilton Health Department, headed by director Barry Bogle, has been monitoring activities and notified neighbors within a 500 foot radius. Bogle says there are a total of 18 homes in that possible impact area.

Finding and Cleaning the Spilled Oil

It’s the job of DEEP workers to find as much of the spilled oil and remove it. They haven’t found a significant amount of it yet, something that doesn’t surprise LeClerc.

The property sits on significant rock ledge, like much of Wilton and Ridgefield. Whatever oil spilled into the ground would begin to seep down through the dirt into the fractures of the bedrock formation below.

“We’ve removed what we can out of the basement, down to the rock, and to water. There were some contaminants, not a lot, but we’re still looking. We’re missing probably 500 gallons of oil. And the realistic answer may be, it may never show up anywhere,” LeClerc adds.

He explained that the bedrock layers are very fractured and cracked. “It’s really hard when it gets into rock like this. You never really know where it goes.”

DEEP will try to track whatever liquid material that moves from the spill location to the areas it will naturally flow. Crews are digging multiple monitoring wells around the property in the direction the oil would likely flow–toward the reservoir and toward the nearest well that is pumping water. They have also drilled a deep well between the house and the closest neighbor to around 400 feet, at the same level of the aquifer, which is where drinking water supply can be monitored.

“At this point we haven’t found any traces of it,” LeClerc says.

Hopefully, the natural topography of the property will help. “If anything, we would like it to migrate down the hillside, and pop out of the hillside where we can dig, or we can recover it,” he adds.

Precautions for the Neighbors–and the Reservoir

LeClerc says there are several precautionary next steps that DEEP is taking.

  • Temporary Drinking Water:   For the house where the spill occurred, and also for the nearest neighbor’s residence, DEEP is taking the wells out of service and will provide temporary drinking water.
  • Neighbors’ Wells Monitored and Treated:   DEEP has offered drinking well monitoring to the 18 neighbors in the 500-ft. radius. “Those will be sampled weekly for the next month. If there’s no detection in those wells, it’ll probably drop down to monthly, and it’ll run that way for a year. If we get any detection then it’ll continue to be weekly, they’ll go on bottled water, and then we will put treatment systems on. The good thing is, fuel oil in groundwater is very easily treated. A carbon filter system takes it out completely.” [Editor’s note: LeClerc explained this would likely be covered by the insurance companies for the tank installer and/or fuel provider.]
         One thing LeClerc was surprised by–some neighbors have declined to have their water checked and monitored. “One of the most difficult challenges at this point is getting the neighbors to agree to have their wells sampled. People just don’t want to. Strange–the first seven houses they went to, everybody said no.”
         The company DEEP has contracted with to do the monitoring is GZA GeoEnvironmental Inc.
  • Reservoir Water Monitored:  DEEP will monitor the wells it has drilled in the direction of the reservoir, and more. “We’re checking the water in the reservoir daily, we’re checking the outfall daily, we have absorbent boom in the lake, we have absorbent boom all on the property line. Those wells will be checked daily for the first month, and then weekly longterm. That’ll probably be realistically years of monitoring. It’s not like if we don’t see it in three months, we walk away from it–those are all permanent monitoring wells. Even if you don’t see it, we want to have the wells in permanently so we can access it if we need. We just want to ensure the safety of the drinking water,” says LeClerc.

The Wilton Health Department will continue to communicate with neighbors and the public about the situation, issuing weekly status reports. LeClerc says DEEP is going to be vigilant about doing as much as possible.

“I think we’re okay. In this case, as long as the neighbors understand that we’re doing the best we can. We’re strongly encouraging them, if they’re in that group of wells, to be sampled, we’re encouraging them to do it. It’s only to protect them. All the insurance companies involved and all the responsible parties are doing everything they can, both from the reservoir perspective, and from the well perspective. And again, it may never show up. When it gets into fractured rock like that, it could have gone straight down, and just disappeared into the rock.”