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Hazardous Waste Cleanup: Union Carbide Caribe, LLC in Peñuellas, Puerto Rico

On this page:

  • Cleanup Status
  • Site Description
  • Contaminants at this Facility
  • Site Responsibility

Cleanup Status

The site is being addressed by Union Carbide Caribe (UCCLLC), under EPA oversight, in two measures. These measures are: Interim Corrective Measures and long-term corrective measures directed at cleanup of the entire site.

The three Group 1 units, those requiring the most immediate attention regarding corrective action, were investigated and, under a 1988 permit, have had their hazardous waste chemically and physically stabilized and left in-place. On-going groundwater recovery and treatment is designed to reduce groundwater contamination and prevent it from moving off-site.

The 10 Group 2 units have been technically closed and, where appropriate, their hazardous waste removed and disposed in accordance with RCRA regulatory requirements.

The 18 Group 3 units have been investigated and 14 do not require further corrective action activities. Of the four remaining units, two will be closed with waste in place and institutional controls will be established to insure that they are not disturbed; one will require that contaminated soils be removed and disposed of appropriately; and one is being further investigated to determine whether contaminated sediments in an open water canal impact fish that are being eaten and impact the local ecosystem.

The four Group 4 units have been investigated and two do not require any further action. Of the two remaining units, there was a concern that groundwater from one unit discharged contaminants to nearby surface waters, but the concentrations of these contaminants have been determined to be so low as to not have a significant impact on human health. The remaining unit requires on-going groundwater recovery and treatment.

Corrective action, in the form of groundwater pumping, was required by the 1988 permit requirements. This requirement, as well as the requirements for closure and cleanup of soil and groundwater for all of the units have been incorporated into the renewal permit, which was issued September 30, 2003. On May 23, 2005, a Public Notice of EPA's Plan to Approve a Proposed Clean Closure Plan for the West Aeration Basin was published in The San Juan Star.

Site Description

The Union Carbide Caribe L.L.C. (UCCLLC) facility, a subsidiary of The Dow Chemical Company, is located on the south coast of Puerto Rico, on State Road 127 in the Municipio (town) de Peñuelas, approximately 7 miles west of the city of Ponce. The site occupies about 900 acres, 680 acres of which are developed, and is on generally level land that has mostly been reclaimed from wetlands by filling. 

The facility was formerly a large petrochemical complex, and is broadly divided into two areas, the Main Plant area, and the Puntilla area. The Puntilla area occupies most of a peninsula extending to the southwest from the Main Plant area. The peninsula extends into the Caribbean Sea, and separates Guayanilla Bay to the west and Tallaboa Bay to the east.

The facility ceased production operations in 1985, although it currently serves as a terminal for the bulk storage of chemical products, operates an industrial wastewater treatment plant, and operates an industrial landfill for the disposal of on-site remediation wastes. The facility is adjacent to a number of mostly non-operating chemical and petroleum refining facilities, the most notable of which is the Commonwealth Oil and Refining Company, Inc. (CORCO), immediately to the north. Otherwise, the land use in the area is generally residential and agricultural. 

Contaminants at this Facility

The major threats are from the unintended release of contaminants from identified Solid Waste Management Units into the soil beneath the facility, into the groundwater within that soil, and to the sediments within an on-site open water canal. These contaminants include: Acenaphthene, Acenaphthylene, Anthracene, Benzene, Benzo(a)anthracene, Benzo(a)pyrene, Chrysene, Ethylbenzene, Fluoranthene, Fluorene, 2-Methylnaphthalene, Naphthalene, Phenanthrene, Pyrene, Styrene,Toluene and Xylenes.

There are 35 of these Solid Waste Management Units that have been identified. Some of these units, specifically surface impoundments (lagoons), were used to intentionally manage hazardous waste on-site. The sludges from these lagoons will be or were dewatered and disposed in an operating industrial landfill on-site.

Because of its relatively high salt content, the groundwater is not currently used for drinking. The released contaminants, however, represent a potential future threat to the surface water of the Caribbean Sea and to its nearshore ecosystem. In addition, some groundwater in the regional area is reportedly used for agriculture and other purposes from unregistered private wells, although these wells are not expected to be impacted by the potential sources of contamination at this site.

Each of the 35 identified Solid Waste Management Units have been categorized into one of four groups for the purpose of prioritizing closure and cleanup. As described in the 1988 operating permit, the groups represent:

  • Group 1 - units that are adjacent to each other, require an operating permit, and have an interim permit to operate; these units shared the same critical cleanup issues;
  • Group 2 - units that have an interim permit to operate and are required to close;
  • Group 3 - units which had not been investigated for releases, and
  • Group 4 - units that are classified as process sewers and had not been investigated for releases. 

Site Responsibility at this Facility

Cleanup at this site is being addressed by the U.S. Environmental Protection Agency (EPA), under authority of the Resource Conservation and Recovery Act (RCRA).