SITE DESCRIPTION: THE JOLIET ARMY AMMUNITION PLANT (JAAP) IS AN ARMY MUNITIONS INSTALLATION LOCATED IN NORTHEASTERN ILLINOIS NEAR CHICAGO. THE LOAD-ASSEMBLY-PACKING AREA (LAP AREA) OCCIPIES ABOUT 14,000 ACRES OF JAAP EAST OF ILLINOIS STATE HIGHWAY 53. PRODUCTION ACTIVITIES THAT WERE CARRIED OUT IN THE LAP AREA DURING ITS OPERATING LIFE FROM THE EARLY 1940'S TO 1977 INCLUDE LOADING, ASSEMBLING AND PACKAGING OF HIGH EXPLOSIVE ARTILLERY PROJECTILES, AERIAL BOMBS AND A VARIETY OF AMMUNITION COMPONENT ITEMS. AMMUNITION TESTING, PRO- JECTILE WASHOUT AND RENOVATION, EXPLOSIVES BURNING AND DEMOLITION WAS ALSO DONE IN THE LAP AREA. SINCE 1977 JAAP HAS BEEN MAINTAINED IN NON-OPERATING STANDBY CONDITION BY THE CONTRACTOR/OPERATOR (UNIROYAL, INC.). ARMY INSTALLATION RESOTRATION STUDIES HAVE DOCUMENTED GROUNDWATER AND SURFACE WATER RELEASES OF MUNITIONS-RELATED CONTAMINANTS, INCLUDING TNT, DNT AND HEAVY METALS, ATTI- BUTABLE TO LAP AREA PRODUCTION ACTIVITIES. THE MAIN WASTE WATER SOURCE FOR THE LAP AREA WAS PINK WATER RESULTING FROM WASHOUT OF REJECTED BOMBS AND FROM WASHING OF EQUIP- MENT AND FLOORS. EVIDENCE OF MUNITIONS-RELATED CONTAIMINA- TION HAS BEEN FOUND IN GROUNDWATER MONITORING WELLS LOCATED NEAR A FORMER WASHOUT FACILITY LEACHING POND. MUNITIONS- RELATED CONTAMINATION HAS ALSO BEEN FOUND IN PRAIRIE CREEK AND DOYLE LAKE SEDIMENTS.