The Rota Power Plant site is located in Songsong Village on the island of Rota in the CNMI. The geographic coordinates of the site are 14°08’12” north latitude, 145°08’09” east longitude.
Based on information presented in the Rota Power Plant Spill Prevention Control and Countermeasure Plan, the Rota Power Plant site operations include the generation of power for the island of Rota, storage of new and used oil, and oil/water separation. The Rota Power Plant site contains four primary aboveground storage tanks (ASTs) as well as day tanks and drum and transformer storage areas. Tank R1 is the main fuel AST and has a capacity of 231,000 gallons. Tank R2 has a storage capacity of 20,000 gallons. Tanks R3 and R4 are ASTs with storage capacities of 5,000 gallons and 9,000 gallons, respectively. Tanks R1, R2, and R3 are used for storage of diesel fuel, and used oil is stored in Tank R4. Drum storage areas are located in the western, central, and northwestern portions of the site. Transformer storage areas are located in the northern and northwestern portions of the site. Two day tanks with capacities of 1,400 gallons each are also located at the facility.
The generator units are located in the main Power Plant building near the center of the site. A pump station is located on the east end of the Tank R3 and R4 containment area. The pump station receives fuel from tanker trucks and transfers it into Tank R1. An abandoned 6-inch diameter pipeline runs along the western portion of the site towards the Philippine Sea.
Two oil water separators (OWSs) were located at the Rota Power Plant site. One OWS is located inside the main Power Plant building and drains to the north of the building into a pit. A second in-ground OWS is piped to the secondary containment areas of Tanks R1, R2, R3, R4, and the drum storage berm located in the western portion of the property. This OWS discharges directly to the ground and does not have secondary containment.
The facility is an operating power plant with aging, failing infrastructure and bad management practices. Aboveground storage tanks and piping at the facility are problematic due to corrosion and lack of maintenance. Intra-facility pipelines are corroded and leak. Insufficient and rudimentary oil water separators and leach fields throughout the site are used to process secondary containment and stormwater runoff. These have been identified to be ineffective at removal of oil, resulting in direct discharges of oil to the subsurface and into near surface groundwater at the facility.
On August 1-10, 2011, EPA performed an assessment of the Rota Power Plant facility to identify the source(s) and extent of contamination and identify the remedial actions necessary to restore the site and improve the current and future management practices to minimize and eliminate potential contaminant release into the environment. The assessment revealed a subsurface oil plume at the facility, which was documented to be within 50 feet of the shoreline. EPA also identified a sheen from the facility entering the nearby harbor.
This oil plume appears to already be impacting waters of the US and if not secured, has the potential to cause additional impact to US waters.
