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Hoff VC

Site Facts

Municipality/County: New Hanover Township, Montgomery
HSCA Site Since: 2011
Primary Contaminants of Concern: chlorinated solvents, oil and gasoline components, pesticides, and PAHs

Updated April 2022

Why is DEP Investigating

Drinking Water Sampling and DEP’s Response

  • Between 2011 & 2013, DEP sampled over 40 nearby homes, business, and schools.
  • Sampling by DEP identified nine residential properties with private wells that had contaminants exceeding DEP’s standards.
  • DEP's responsibility under the Hazardous Sites Cleanup Act (HSCA) is to select a remedy that is protective of human health and the environment and complies with all statutory and regulatory requirements.
  • In 2012, DEP held a public meeting to discuss the installation of public waterline to the affected residents.
  • On March 1, 2013 DEP issued a Statement of Decision (PDF) for the Site, selecting the extension of a public waterline as the remedy for contaminated drinking water at the Site. The cost of the construction of the waterline extension was funded by DEP through a grant to New Hanover Township.
  • In 2014, 27 total properties, including the nine residential properties with exceedances, were connected to the extended waterline.

Source Investigation and DEP’s Response

  • Between the 1960s to late 1980s, Swann Oil Company, a heating oil distributor, operated at the Site.
  • In the early 1970s, the Swann Oil company was cited several times by DEP’s predecessor, the Pennsylvania Department of Environmental Resources, as well as the Pennsylvania Department of Health for illegal discharges of hazardous substances, including a chlorinated solvent, from a truck-wash to an unnamed tributary of Swamp Creek. Swann Oil also had several oil and kerosene spills during its operation.
  • In the early 1990s, the Site was purchased by its current owner, the Good Oil Company. The Good Oil Company removed many of the Aboveground Storage Tanks and Underground Storage Tanks (UST) improperly and punctured an UST while drilling a monitoring well. DEP’s Storage Tanks Corrective Program has filed orders and liens against Good Oil. Whitetail Disposal Company currently leases property from Good Oil as a truck staging area. In the early 2000’s, Gibraltar Rock Inc. (GRI) purchased several parcels of land less than ½ mile from the Site for a future quarrying operation.
  • Between 2011 & 2014 DEP’s investigation activities included the installation of monitoring wells, surface water sampling, and a vapor intrusion investigation. Details of these activities can be found in the 2014 Project Investigation Report prepared by Leidos on behalf of DEP.
  • August 2016 Groundwater Modeling and Fate and Transport Analysis (PDF) prepared by Tetra Tech, Inc on behalf of DEP.

Concrete Pit Prompt Interim Response

  • In 2016, DEP located a concrete pit on the source property which contained hazardous waste. DEP subsequently removed 8000 gallons of hazardous waste from the concrete pit and 217 tons of contaminated soil surrounding the pit as part of a Prompt Interim Response. The Statement of Decision (PDF) was finalized in June 2017.

Groundwater Remediation Pilot Study

  • In 2018, DEP initiated an in-situ remediation pilot study to address remaining groundwater contamination, which included the installation of five monitoring/injection wells near the concrete pit.
  • October 2020 Innovative Environmental Technologies Inc. (IET) proposal (PDF) to perform in-situ chemical oxidation for the treatment of source and residual contamination via ferric oxide activated persulfate with pH control.
  • In November 2020, sodium and potassium persulfate and iron were injected into the shallow groundwater to degrade the contaminants near the concrete pit.
  • In September 2021, in-situ chemical reduction socks were installed in several injection/monitoring wells to further degrade the contaminants.
  • DEP conducted groundwater sampling on a routine basis following the injections to monitor the effectiveness of the injections. The figure below compares results before and after the injections.
  • DEP determined that another injection event was necessary to gather additional data regarding the effectiveness of in-situ remediation of the groundwater, by conducting additional injections.
  • The injections are planned to begin in mid-Spring 2022.

Timeline (New April 2022)

= Completed Steps,  = Current Step,  = Next Steps

VOCs detected in Private Drinking Water Well above MCLs7/2011
Drinking water sampling07/2011- 9/2014
Drinking Water Interim Response Proposal10/17/2012
Public Hearing12/4/2012
Issuance of the Statement of Decision (SOD) and Response to Public Comments3/1/2013
Completion of Drinking Water Interim Response9/2014
Installation of Site Monitoring Wells04/2012-Ongoing
Sampling of Monitoring Wells05/2012-Ongoing
Issuance of the Project Investigation Report8/2014
Discovery of Concrete Pit7/2016
Concrete Pit Prompt Interim Response Proposal11/4/2016
Public Hearing12/6/2016
Issuance of the Statement of Decision (SOD) and Response to Public Comments6/9/2017
Completion of Concrete Pit Prompt Interim Response6/2018
Initiation of Pilot Study1/2019
ISCO injections (Phase I)11/2020
In-Situ Sleeves Deployment (Phase 2)9/2021
Additional ISCO injections (Phase 3)Est. Spring 2022
Additional In-situ Sleeves Deployment (Phase 4)Est. Summer 2022
Pilot Study ReportEst. Summer 2022

Contacting DEP

Please direct correspondence or inquiries to one of the following:

  • Site Information: Colin R. Wade, Project Officer, at 484-250-5722 or
  • Community and Media Relations: Stephanie Berardi, Community Relations Coordinator at 484-250-5808 or
  • Legislative Inquiries: Rob Fogel, Local Government Liaison, at 484-250-5817 or

To schedule an appointment to review files associated with this Site and project, please call the Norristown Office at 484-250-5910.

Municipality Information

New Hanover Twp: Phone: (610) 323-1008,

Information regarding the proposed Gibraltar Rock quarry in New Hanover Township.