Deletion from the National Priorities List

Deletion From the National Priorities List

SUPPLEMENTARY INFORMATION:

The NPL, created under section 105 of CERCLA, as amended, is an appendix of the NCP. The NCP establishes the criteria that EPA uses to delete sites from the NPL. In accordance with 40 CFR 300.425(e), sites may be deleted from the NPL where no further response is appropriate. Partial deletion of sites is in accordance with 40 CFR 300.425(e) and are consistent with the Notice of Policy Change: Partial Deletion of Sites Listed on the National Priorities List, 60 FR 55466 (November 1, 1995). The sites to be deleted are listed in table 1, including docket information containing reference documents with the rationale and data principally relied upon by the EPA to determine that the Superfund response is complete. The NCP permits activities to occur at a deleted site, or that media or parcel of a partially deleted site, including operation and maintenance of the remedy, monitoring, and five-year reviews. These activities for the site are entered in table 1 in this SUPPLEMENTARY INFORMATION section, if applicable, under Footnote such that; 1= site has continued operation and maintenance of the remedy, 2= site receives continued monitoring, and 3= site five-year reviews are conducted. As described in 40 CFR 300.425(e)(3) of the NCP, a site or portion of a site deleted from the NPL remains eligible for Fund-financed remedial action if future conditions warrant such actions.

Information concerning the site to be deleted from the NPL, and the proposed rule for the deletion of the site, are included in table 2.

For the site proposed for deletion, the closing date for comments in the proposed rule was October 14, 2025. The EPA received six submissions for the Corozal Well site, each with multiple comments. The EPA prepared a Responsiveness Summary to address public comment for the Corozal Well site full deletion. The EPA placed the public submissions with comments and Responsiveness Summary for the Corozal Well site in the docket specified in table 1, on https://www.regulations.gov, and in the appropriate Regional Records Center listed in the ADDRESSES section.

Commenters for the Corozal Well site expressed concerns that the site proposed for deletion may still contain contamination. Groundwater sampling data and additional statistical analysis indicate that site contaminants of concern have all been below their remediation goals. In addition, maximum contaminant levels at all site wells are consistently decreasing or on stable trends. Accordingly, sampling establishes that the site does not contain contamination exceeding the maximum contaminant levels. All appropriate response actions under CERCLA have been completed. The remedy implemented at the site has achieved all remedial action objectives, the cleanup levels identified in the decision documents, and is consistent with agency policy and guidance. The EPA clarified it has determined that the implemented actions at the Corozal Well site are protective of human health and the environment. EPA has achieved cleanup levels and remedial action objectives for groundwater, and the remedy allows for unrestricted use of the groundwater. Groundwater sampling data and additional statistical analysis indicate that site contaminants of concern have all been below their remediation goals and maximum contaminant levels at all site wells with consistently decreasing or stable trends.

Other commenters expressed concern about groundwater contamination and potential source areas recontaminating the groundwater. EPA conducted source area investigations by first conducting a broad screening of soil gas around the site. The data collected in the remedial investigation did not indicate the presence of a contamination source in the soil that would continue to impact groundwater. The data quality program complied with throughout the remedial action was sufficiently rigorous to enable EPA and PRDNER to determine that remedial actions were completed as designed.

Commenters also expressed concern about the lack of water quality data for the Santana Well prior to 2010 and wanted to know who would be responsible for regulating the well into the future if the site is deleted. Agencies in Puerto Rico will be responsible for any continued monitoring and maintenance of the well. PRDNER regulates installation of wells and issues well franchises, and the Puerto Rico Department of Health (PRDOH) regulates the operation of a water system. The Santana Well System has been regulated by the PRDOH since 2007 before the site was included on the NPL to ensure that water distributed to the public met drinking water standards; that will continue to occur after the site is deleted from the NPL. Public comments were carefully considered in the EPA's final decision to delete the Corozal Well site from the NPL. The EPA is proceeding with the full deletion action as originally proposed. The EPA concluded the deletion criteria for the site were met. EPA's decision and supporting documentation is provided in the specified docket.

The EPA maintains the NPL as the list of sites that appear to present a significant risk to public health, welfare, or the environment. Deletion from the NPL does not preclude further remedial action. Whenever there is a significant release from a site deleted from the NPL, the deleted site may be restored to the NPL without application of the hazard ranking system. Deletion of a site from the NPL does not affect responsible party liability in the unlikely event that future conditions warrant further actions.

For reasons set out in the preamble, the EPA amends 40 CFR part 300 as follows:

PART 300-NATIONAL OIL AND HAZARDOUS SUBSTANCES POLLUTION CONTINGENCY PLAN