Current Site Information
EPA Region 3 (Mid-Atlantic)Delaware
New Castle County
EPA ID# DED981035520
1st Congressional District
Last Update: January 2015
EPA will provide future updates on an as-needed basis.
Current Site Status
The site was deleted from the National Priorities list (NPL) on July 1, 1997. The Environmental Protection Agency (EPA) determined that its removal action had adequately addressed the conditions at the site, and that the site no longer posed a threat to human health or the environment, and that no further action was required. The removal action consisted of removing on-site drums and tanks filled with wastes and 122 yards of solid waste, applying a one foot clay cap and installing ground water monitoring wells. Thus, EPA signed a Record of Decision (ROD) calling for No Action on September 30, 1991. The site was deleted from the National Priorities list on July 1, 1997.
The Sealand Limited Site, located in Mt. Pleasant Delaware (1st Congressional District) is a former waste oil recycling operation that was abandoned by the owner in August of 1983, after approximately one year of operation. When a subsequent investigation by the State of Delaware found evidence of leaking drums and tanks on the abandoned site, EPA initiated an emergency removal action. The action included the removal of 240,000 gallons of coal tar, 320 drums, and 122 cubic yards of solid waste from the site. Waste oil storage tanks were cleaned and moved offsite, and the tank and drum storage area was capped with one foot of clay and six inches of top soil. Monitoring wells installed during this action showed the ground water under the site was contaminated with polynuclear aromatic hydrocarbons. Analyses of the contents of the tanks and drums and site soil detected polycyclic aromatic hydrocarbons (PAHs), creosotes, solvents, and other toxic organic compounds. The area surrounding the site is primarily agricultural and residential. Private wells within 3 miles of the site provide drinking water to an estimated 1,000 people.
Site ResponsibilityCleanup of this site was the responsibility of Federal and State governments, and parties potentially responsible for site contamination.
NPL Listing HistoryThis site was proposed for to the National Priorities List of the most serious uncontrolled or abandoned hazardous waste sites requiring long term remedial action on June 24, 1988. The site was formally added to the list on August 30, 1990, and deleted on July 7, 1997.
Threats and Contaminants
Low levels of PAHs, creosotes, solvents, and other toxic compounds from the former recycling operation were found in onsite soils. However, because of the emergency actions undertaken by EPA, levels of soil contaminants are now below health-based standards and do not pose a risk to individuals who may come into contact with the soil.
Contaminant descriptions and risk factors are available from the Agency for Toxic Substances and Disease Registry, an arm of the CDC.
In December of 1988, EPA entered into an Administrative Order on Consent with 14 potentially responsible parties under which the parties agreed to conduct a study of the nature and extent of contamination at the site, and to evaluate cleanup options. Based on the site sampling results, EPA determined that the removal action had adequately addressed the conditions at the site, that the site no longer posed a threat to human health or the environment, and that no further action was required. Thus, EPA signed a ROD calling for No Action on September 30, 1991. The site was deleted from the National Priorities list on July 1, 1997.