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-MIGRATING LANDFILL GAS FROM THE PERIMETER OF THE NORTHERN PORTION OF THE SITE. LANDFILL GASES WERE BEING MEASURED AT MONITORING POINTS WITHIN THE BASEMENTS OF STRUCTURES ADJACENT TO THE SITE AT LEVELS EXCEEDING 100 PERCENT OF THE LOWER EXPLOSIVE LIMIT (LEL).