The DNREC Division of Waste and Hazardous Substances will conduct a virtual public hearing (Docket #2020-R-WH-0008) on the Proposed Plan of Remedial Action for the General Motors Corp. Wilmington Assembly Plant Operable Unit 4 (DE-1149). Public Comment Period Closed.

Operable Unit 4 (OU-4) is part of the former assembly plant located in Wilmington, Delaware. Soil at OU-4 was not impacted. OU-4 groundwater was impacted by ethylbenzene, 1,2,4-trimethylbenzene, xylene, and naphthalene. Groundwater contamination migrated offsite to the northeast. As the groundwater travels from the site, contamination reduces and does not impact any offsite drinking water wells. Indoor air samples from Townhouses on Dodson Avenue do not indicate a risk from groundwater to indoor air. The contamination at OU-4 will be addressed by groundwater monitoring, restricting OU-4 to commercial use, limiting groundwater use, and requiring soil/groundwater management plan during redevelopment.

Details of the Proposed Plan are available online at www.nav.dnrec.delaware.gov/DEN3/. For additional information on the Proposed Plan, contact Rick Galloway, Project Manager, at 391 Lukens Drive, New Castle, DE, 19720, by telephone at (302) 395-2600, or by email at RS_Public_Comments@delaware.gov

Please note that live comments will not be accepted during the virtual hearing. Written comments may be submitted to the Hearing Officer via the online comment form at dnrec.delaware.gov/public-hearings/comment-form/, via email to DNRECHearingComments@delaware.gov, or via USPS to the below address.

Public Hearing Officer

Lisa A. Vest
DNREC Office of the Secretary
89 Kings Highway
Dover, DE 19901

Transcript, Hearing Officer’s Report and Secretary’s Order

Public Hearing Transcript

Hearing Officer’s Report

Secretary’s Order No. 2020-WH-0018 — Approving the Proposed Plan of Remedial Action for the General Motors Wilmington Assembly Plant – Operable Unit 4

Related Links

Public Meeting Calendar Notice

DNREC Public Notice

Proposed DNREC Exhibits

Exhibit 1 – November 28, 1990 – No further action (NFA) letter from DNREC.

Exhibit 2 – June 2011 – Background Indoor Air Concentrations of Volatile Organic Compounds in North American Residences (1990 – 2005): A Compilation of Statistics for Assessing Vapor Intrusion Report

Exhibit 3 – July 2014 – Vapor Intrusion and Groundwater Delineation Investigation Report-Dodson Avenue Offsite Investigation (OU-4). (This report is also Appendix B of the July 17, 2015 Remedial Investigation Report.)

Exhibit 4 – July 18, 2014 – Focused Feasibility Study-Interim Vapor Phase Remediation

Exhibit 5 – July 17, 2015 – Remedial Investigation Report
– Appendix A
– Appendix B
– Appendix C
– Appendix D
– Appendix E
– Appendix F
– Appendix G
– Appendix H

Exhibit 6 – August 14, 2015 – Operable Unit 4-Additional Characterization Work Plan

Exhibit 7 – June 14, 2018 – Soil Vapor Extraction System Evaluation Work Plan (OU-4)

Exhibit 8 – July 27, 2019 – Supplemental Vapor Intrusion Risk Evaluation OU-4

Exhibit 9 – August 5, 2019 – Soil Vapor Extraction System Report OU-4

Exhibit 10 – January 16, 2020 – Feasibility Study for OU-4

Exhibit 11 – March 8, 2020 – Affidavit of Legal Notice for Proposed Plan of Remedial Action & Public Hearing for OU-4

Exhibit 12 – March 8, 2020 – Proposed Plan of Remedial Action for OU-4

Exhibit 13 – March 26, 2020 – Email for Rick Galloway notifiying the stakeholders that the public hearing will be a virtual online hearing

Exhibit 14 – April 5, 2020 – Affidavit of Legal Notice that the April 9, 2020 public hearing will be held as a virtual hearing online

Exhibit 15 – April 9, 2020 – Public Hearing Presentation regarding the Proposed Plan of Remedial Action-OU-4, General Motors Corp-Wilmington Assembly Plant
– References: EPA Indoor Air Quality page and Delaware DHSS Indoor Air Quality page