Proposed Plan of Remedial Action for the General Motors Corp. Wilmington Assembly Plant OU- 4 (DE-1149)

The Department invites public comment on a proposal to clean up Operable Unit 4 (OU-4), a portion of the General Motors Corp. Wilmington Assembly Plant located in Wilmington, Delaware.  OU-4 soil 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. 

DNREC-RS will hold a Public Hearing on the Proposed Plan for OU-4 on Thursday, April 9, 2020 from 6 pm to 8 pm at the DNREC-Remediation Section Offices, 391 Lukens Drive, New Castle, DE. This public hearing is identified on the Hearing Docket as Hearing Docket No.:  2020-R-WH-0008. 

Details of the Proposed Plan are available at the office of DNREC-RS (391 Lukens Drive, New Castle, DE, 19720), or online at

The comment period ends on March 30th, 2020.  For additional information, please contact Rick Galloway, Project Manager at (302) 395-2600 or via email to