FACT SHEET ROI POWER PLANT FUEL SPILL SITE

CLEANUP

1.0 INTRODUCTION In 1996, 22,500 gallons of diesel fuel was spilled on the ground at the Roi Power Plant Spill Site. The Roi power plant provides electrical power to facilities on the island of Roi-Namur. Diesel fuel for the power plant generators is stored in two large-capacity storage tanks currently located inside a large secondary containment basin. The 5-acre site sits on top of 5-8 feet of fill materials, as the original islands were joined by extensive earthwork in the years following World War II.

Historical records also show other possible sources: a former power plant, wash rack, drainage ditch, oil pit, and drain field.

Roi Power Plant Site Location on Roi-Namur

Roi Power Plant Site Investigation Area Groundwater beneath the site lies at depths of about 4 feet below the ground surface; the groundwater depth varies with daily tidal fluctuations across a large portion of the site. The site is located in the industrial area of the island; the nearest residences are over 1 mile away. The site groundwater is not used for drinking water purposes, but small amounts of the site groundwater may be discharging into the lagoon.

2.0 CONTAMINATION NATURE AND EXTENT Following the fuel spill, spill response efforts are believed to have recovered 75% of the spilled fuel. Site Investigations performed in 2011 confirmed a large area of petroleum contamination and low amounts of solvents in the soil and groundwater. The apparent sources are the 1996 spill and previous site operations. The nature of the contamination is mostly fuel-related, with trace amounts of solvents and other chemicals.

The detected extent of contamination suggests spilled fuel moved straight down into the ground and then spread out on top of the groundwater surface.

Most of the shallow soils in the contaminated area outside of the spill area have lower levels of contamination than the deeper soils near the groundwater. Over time, the tidal effects on the groundwater spread the fuel over a wider area and much of the fuel is trapped in the soil.

The approximate extent of soil contamination.

Figure showing where fuel contamination is floating on groundwater table and proposed infiltration galleries to remove the fuel

3.0 CLEANUP APPROACH The preferred cleanup approach has two phases. The first phase removes the fuel floating on the groundwater table. The second phase deals with soil and groundwater contamination after the fuel is removed. The first phase activity (fuel removal) is time-critical because it removes petroleum from the soil and groundwater and is required before the second phase can be effective. Fuel collection techniques considered and further described in the Removal Action

Memorandum include infiltration galleries, dual-phase extraction, and bioslurping. Preferred techniques use methods that operate passively, below ground, using natural tidal effects to move and flush the petroleum contamination out of the soil and groundwater. The proposed approach is to use infiltration galleries (horizontal slotted piping placed underground near the top of the groundwater table) to collect fuel from the subsurface. The recovered fuels will be measured, tested, and reused beneficially (such as incinerator fuel) if testing results allow. The Army plans to begin phase one cleanup efforts in June 2012.

Schematic of an infiltration gallery. The second phase of the cleanup effort will take a longer time (several years). Cleanup techniques for the second phase will be evaluated in a Feasibility Study and bioremediation is expected to be a component of the final remedy. Bioremediation utilizes naturally occurring bacteria (fed with oxygen and nutrients) to help break down and digest the fuels. Bioremediation will be used to cleanup soil and groundwater and minimize impacts to the lagoon and marine environment.

4.0 INVESTIGATIONS Supplemental sampling activities and the initial pilot testing activities are still underway at the Roi Power Plant Fuel Spill Site. The supplemental sampling results are being merged with previously collected data in the Site Investigation and Data Evaluation reports. All of the data will be used to design phase two of the cleanup effort. The Data Evaluation Report is expected to be available for public review and comment during the late summer of 2012. Human health risks are currently limited to exposure (ingestion, skin contact, etc) to subsurface contaminated soil or groundwater directly on the site. Site workers during the proposed cleanup will wear appropriate protective equipment to minimize health risks. A comprehensive risk assessment is underway for current and future site occupants. The potential impacts to the lagoon will also be investigated in 2013. Future work may include ecological risk assessments and biological sampling surveys to identify damage to the marine ecosystem.

5.0 SITE INFORMATION REPOSITORIES The Roi Power Plant Removal Action Memorandum, April 2012, is currently available for public review at the following locations:

• US Army Kwajalein Atoll Grace Sherwood Public Library (on Kwajalein)

• US Army Kwajalein Atoll Roi-Namur Library (on Roi-Namur)

• Republic of the Marshall Islands Environmental Protection Authority Office (on Majuro)

Computer users with internet access can download documents and information related to the cleanup activities at the US Army Kwajalein Atoll Cleanup website (www.usakacleanup.info). Questions about the site cleanup plan can be directed by phone to Mr. Anthony Hoover, USAKA Environmental Engineer, (808)355-5449. Written comments on the Roi Power Plant Fuel Spill Site cleanup plan can be made one of three ways: 1) through the www.usakacleanup.info comment portal for the Roi

Power Plant RAM document, 2) emailed to comments@usakacleanup.info, or 3) mailed to Sivuniq Inc.; Attn: Roi Power Plant RAM Comments;

APO, AP 96555. All comments must be received by May 30, 2012.