THIS ORDER REQUIRES THE RESPONDENTS, NICOR GAS AND CHICAGO HEIGHTS IRON & SUPPLY, TO CONDUCT REMOVAL ACTIVITIES TO ABATE AN IMMINENT AND SUBSTANTIAL ENDANGERMENT TO THE PUBLIC HEALTH, WELFARE OR THE ENVIRONMENT THAT MAY BE PRESENTED BY THE ACTUAL OR THREATENED RELEASE OF HAZARDOUS SUBSTANCES AT OR FROM THE SITES. RESPONDENT NICOR SHALL REIMBURSE U.S. EPA FOR ALL RESPONSE COSTS INCURRED BY THE UNITED STATES IN OVERSEEING NICOR'S IMPLEMENTATION OF THE REQUIREMENTS OF THIS ORDER. VIOLATION OF ANY APPLICABLE PROVISION OF THIS ORDER MAY SUBJECT RESPONDENTS TO CIVIL PENALTIES.