WELLFLEET — State officials want to see the cleanup of a nearly two-year-old oil spill at a downtown business and recently threatened the owner with fines “in excess of several thousand dollars” if the work isn’t done.

The spill occurred in September 2021, when landscapers from J.F. Young accidentally damaged a feed line to a 275-gallon above-ground oil tank behind the Box Lunch at 50 Briar Lane while clearing vegetation.

Heating oil from the tank leaked onto the ground and into a nearby wetland, contaminating vegetation and some standing water.

Wellfleet Box Lunch owner Kathryn MacNutt hired Frank Corp. Environmental to perform an initial emergency cleanup, and over the next several days they installed oil-absorbent booms in the wetland and siphoned out more than 10,000 gallons of oily water with a vacuum truck.

Polyethylene sheeting lined and covered a hay-bale berm at the perimeter of the affected area to prevent migration of the oil. Workers dug up contaminated soil and vegetation, which they covered in plastic sheeting and left on the property.

The private well that supplies drinking water to the Box Lunch was tested for petroleum contamination in November 2021 and none was detected.

The Mass. Dept. of Environmental Protection (DEP) was notified shortly after the spill occurred, which triggered a set of cleanup requirements and deadlines. But after that initial burst of remedial action, progress stalled. None of the required benchmarks was met after November 2021. The piles of contaminated soil remain on the site today.

Most oil and hazardous material releases are cleaned up within a year, according to a DEP spokesperson. In the case of the Box Lunch, the property owner’s “overdue response actions” led the state agency to issue a notice of noncompliance.

In April, the DEP sent letters to McNutt and to landscape company owner Jeremy Young, listing the violations to date. A release notification form that must be submitted within 60 days of a spill had not arrived, nor had an immediate response action plan. The site still lacked a tier classification, a designation that identifies the level of cleanup and oversight needed, and a Phase 1 report, which describes measures taken to evaluate the extent of the contamination.

MacNutt has since hired Weston & Sampson engineers, who provided the overdue paperwork, including a site investigation report, to the DEP by its July 24 deadline.

Weston & Sampson has begun its investigation of the site, sampling the soil and installing groundwater monitoring wells. Six shallow soil samples, three groundwater samples, and two surface water samples were then analyzed for petroleum hydrocarbons.

One of the two surface water samples exceeded the limit for several polycyclic aromatic hydrocarbons, which are found in crude oil and gasoline. Some petroleum contamination was found in the groundwater samples, but only benzene reached a level requiring cleanup in one well.

Three soil samples contained levels of polycyclic aromatic hydrocarbons at levels requiring cleanup, and two of the three also contained volatile organic compounds requiring cleanup.

There is a stream on the property being watched by Weston & Sampson engineers, which does not appear to have been contaminated.

Weston & Sampson gave the site a Tier 1 designation because of the benzene and the stockpile of contaminated soil and vegetation, which must be taken offsite to a disposal facility.

What’s been done to date is only a first step.

In its report, Weston & Sampson outlines the next phase of work, which will focus on further assessment of soil, groundwater, and surface water. Engineers will “evaluate the risk to human health and the environment and determine if further remedial measures are warranted.” They expect Phase II to be completed by 2025.

According to the DEP spokesperson, a progress report must be submitted to the agency in December for the cleanup to stay on track.

Town Administrator Rich Waldo and Health and Conservation Agent Meredith Ballinger were both contacted for this story, since they also received related notice from DEP. Neither responded by this week’s deadline. Young and MacNutt did not return calls for comment.