TETRA TECH, INC.

THE CONTRACTOR SHALL PROVIDE TECHNICAL ASSISTANCE TASKS TO SUPPORT AGENCY OVERSIGHT OF REMOVAL SITE EVALUATIONS (RSES), INTERIM REMOVAL ACTIONS, ENGINEERING EVALUATION AND COST ANALYSIS (EE/CA), AND ANY OTHER ACTIVITY AT THE ABANDONED URANIUM MINES (

THE PURPOSE OF THIS TASK ORDER IS TO PROVIDE TECHNICAL SUPPORT TO EPA REGION 6 IN FULFILLMENT OF ITS RESPONSIBILITIES FOR OVERSIGHT AND ENFORCEMENT OF ARCO'S ONGOING RI/FS UNDER THE ASAOC AND TO ASSIST EPA IN COORDINATION AND COMMUNICATION WITH

THE PURPOSE OF THIS NO-COST, BILATERAL MODIFICATION IS TO EXTEND THE POP END DATE BY TWELVE (12) MONTHS FOR RUBY MINES - NAVAJO NATION AUM RESPONSE ASSESSMENT AND EVALUATION SERVICES (RAES) II FOR EPA FOR REGIONS 6 & 9..

THE PURPOSE OF THIS NO-COST, BILATERAL MODIFICATION IS TO EXTEND THE PERIOD OF PERFORMANCE FOR UAV SUPPORT ON NAVAJO NATION IN ACCORDANCE UNDER THE RAES2 CONTRACT #68HE0923D0002 FOR EPA FOR REGIONS 6 & 9.

P00007 - LEVEL-OF-EFFORT (LOE) AND FUNDING INCREASE, TO 0015 NAUM PROGRAM DEVELOPMENT & SUPPORT - NAVAJO NATION AUM RESPONSE ASSESSMENT AND EVALUATION SERVICES (RAES) II FOR EPA FOR REGIONS 6 & 9.

ENVIRONMENTAL ASSESSMENT REPLACEMENT OF THE AIR ROUTE SURVEILLANCE RADAR (ARSR) ON MT. KA`ALA, OAHU, HAWAII

THE PURPOSE OF THIS BILATERAL MODIFICATION IS TO INCREASE THE LEVEL-OF-EFFORT AND FUNDING; TO 16 UNDER RAES 2 CONTRACT #68HE0923D0002.

THE PURPOSE OF THIS MODIFICATION IS UPDATE THE SCOPE OF WORK TO INCLUDE ADMINISTRATION, MAINTENANCE, AND SUPPORT FOR NAUM SERVER INFRASTRUCTURE (TASK 7), ADD FUNDING TO CONTINUE WORK TASKS WITHIN ORIGINAL SOW AND MODIFICATIONS AND EXTEND THE PERIOD O

THE PURPOSE OF THIS NO-COST MODIFICATION IS TO EXTEND THE PERIOD OF PERFORMANCE FOR R6 SCMB- TO 23 - NAVAJO NATION AUM RESPONSE ASSESSMENT AND EVALUATION SERVICES (RAES) II FOR EPA FOR REGIONS 6 & 9.

THE PURPOSE OF THIS MODIFICATION IS TO REPLACE THE PRIMARY TOCOR WITH A NEW PRIMARY. THE PREVIOUS PRIMARY TOCOR SHALL BECOME THE ALTERNATE TOCOR.

THE PURPOSE OF THIS NO-COST, BILATERAL MODIFICATION IS TO EXTEND THE PERIOD OF PERFORMANCE AND ADD A NEW ALTERNATE TOCOR. THE CONTRACTOR SUPPORTS AGENCY OVERSITE OF RSES,, INTERIM RAS, WATER STUDIES, EE/CAS, AND RAS AUMS IN THE PHASE 2 EXPANDED TRUST

THE PURPOSE OF THIS NO-COST BILATERAL MODIFICATION P00006 IS TO EXTEND THE PERIOD OF PERFORMANCE. THE CONTRACTOR SHALL PROVIDE SUPPORT NEEDED FOR NTCRA PLANNING AND OVERSIGHT ON BABBITT RANCHES UNDER RAES 2 CONTRACT #68HE0923D0002.

THE PURPOSE OF THIS NO-COST, UNILATERAL MOD IS TO ADD AND REMOVE A TOCOR. TO IS FOR AGENCY OVERSIGHT OF UNC/GE WORK AT NECR MINE SITE UNDER RAES 2 CONTRACT.

THE PURPOSE OF BI-LATERAL MODIFICATION IS TO EXTEND THE POP. CONTRACTOR WILL PERFORM EE/CAS AT THE SECTION 32/33 MINES FOR THE RAES II CONTRACT.

THE PURPOSE OF THIS BIILATERAL MOD IS TO INCREASE THE LOE AND FUND THE ADDITIONAL LOE. THE CONTRACTOR SHALL PROVIDE EVALUATIONS FOR KNOWN 278 UNFUNDED AUMS ON THE NAVAJO NATION UNDER RAES II FOR EPA FOR REGIONS 6 & 9.

THE PURPOSE OF THIS MODIFICATION IS TO INCORPORATE A REVISED STATEMENT OF WORK AND ADD AN ALTERNATE TASK ORDER COR (TOCOR).

THE PURPOSE OF THIS BILATERAL MODIFICATION IS TO INCREASE THE LOE FOR N. AGENCY EE/CA - TO #0007 (DO #68HE0923F0051) ON RAES2 CONTRACT #68HE0923D0002.

THE PURPOSE OF THIS BILATERAL MODIFICATION IS TO EXTEND THE POP. CONTRACTOR WILL PERFORM EE/CA TASKS AT THE QUIVIRA MINE FOR THE RAES 2 CONTRACT.

P00006: MOD TO CORRECT CLIN 0001 POP: TO 0002: COMMUNITY INVOLVEMENT OUTREACH SUPPORT FOR NAVAJO NATION AUM RESPONSE ASSESSMENT AND EVALUATION SERVICES (RAES) II FOR EPA FOR REGIONS 6 & 9.

P00009 RAES 2 - INCREASE CEILING AMOUNT AND INCORPORATE A CLAUSE- NAVAJO NATION AUM RESPONSE ASSESSMENT AND EVALUATION SERVICES (RAES) II FOR EPA FOR REGIONS 6 & 9.

THE PURPOSE OF THIS MODIFICATION IS TO EXTEND THE PERIOD OF PERFORMANCE.

THE PURPOSE OF THIS BILATERAL MOD IS TO EXTEND THE PERIOD OF PERFORMANCE. CONTRACTOR SHALL PROVIDE TECHNICAL DESIGN SERVICES FOR PLANNING & CONDUCTING CLEANUP VERIFICATION UNDER THE RAES 2 CONTRACT #68HE0923D0002 FOR REGIONS 6 & 9.