THIS IS A UNILATERAL ADMINISTRATIVE ORDER EMERGENCY RESPONSE AT AN NPL SITE TO EFFECTUATE AN INTERIM, ACTIVE LANDFILL GAS MANAGEMENT SYSTEM DESIGNED TO INTERCEPT LATERALLY-MIGRAT ING LANDFILL GAS FROM THE PERIMETER OF THE NORTHERN PORTION OF THE SITE. LANDFILL GASES WERE BEING MEASURED AT MONITOR- ING POINTS WITHIN THE BASEMENTS OF STRUCTURES ADJACENT TO THE SITE AT LEVELS EXCEEDING 100 PERCENT OF THE LOWER EXPLOSIVE LIMIT (LEL).