Amended Proposed Plan of Remedial Action for 415-427 Tatnall Street Property (DE-1248)

Division of Waste and Hazardous Substances

Published: Jan. 4, 2023
Comments Due: Jan. 24, 2023

The Department invites public comment on an amended proposal to clean-up the 415-427 Tatnall Street (DE-1248) located at 415-427 Tatnall Street location in Wilmington. The site is a two-story building with basement and parking lot of approximately nineteenths of an acre (0.09). The lot was previously used by a printing company.

Mariko Ueno will be subject to the following key remedial actions: the submittal of a Contaminated Materials Management Plan (CMMP), which specifies the methods used to manage future groundwater and soils at the site and a Long-term Stewardship Plan (LTS) which will be used to monitor the natural attenuation of the groundwater to meet DNREC’s Hazardous Substance Cleanup Act (HSCA) standards. Following the development and compliance with the CMMP and recording of an Environmental Covenant (EC) restricting groundwater withdrawal, a request for Certification of Completion of Remedy (COCR) must be submitted and processed.

Details of the Proposed Plan are available online at:

The comment period ends on January 24, 2023. For additional information, please contact Tracy Spinden, Project Manager at (302) 395-2600 or via email at