# CENTRAl MAl POWER

June 20, 2012 i.Vfr. Terrence Connelly U.S. EnvironmentalProtection Agency 5 Post Office Square, Suite 1.00 Mail Code OSRR07-1 Boston, MA 02109-3912 RE: O'connor Company Superfund Site Pre-Certification Inspection and 2012 Soil Sampling Dear Terry, Central Maine Power (CMP) is pleased to provide this letter in response to your letter of May 18,2012. In accordance with paragraph 51 ofthe 1991 Consent Decree, CMP (the Settling Defendant) concludes that the Work (as defined in the Consent Decree) outlined in the l 989 Record of Decision (ROD), 1994 Explanation of Significant Differences (ESD), 1995 Contingency Remedy, 2002 ROD Amendment, and the 2003 Amendment to Consent Decree has been fully performed. The Work at the site has been divided into three operable units as described below:

> OU-1- Source Control The Source Control Remedial Action (operable 

### unit OU1) required removal of soil contaminated 1.vith PCBs or cPAHs over 1 0 ppm, or lead over 248 ppm, and consolidation ofsoils with PCBs and cPAHs between l and 10 ppm into a "Designated Area". The Designated Area was to be covered with 12 inches ofclean soiL Wetlands were to be restored in the Upland Marsh, Upper Lagoon, and Lower Lagoon. This work was completed in November !997.

, OU-2 

### -Management of Migration Groundwater has been monitored at the site since 1986, and groundwater performance standards were set for 8 compounds (7 VOCs and PCBs). In 2002 the ROD was amended to include a Tecllirical Impracticability determination that the groundwater in a 3-acre zone around former Transformer Work Area III (TI Zone) would not meet groundwater standards in a realistic time period, and the cleanup standards for this zone were waived. Groundwater quality outside the TI Zone has improved continuously since Source

lBERDROLA USA.**Mrc!'erral1ce.Go@~lly.** 

### Page2of2 ·· ·· · ' '"''""" '" 

### Jllne20; 2012

Coriti:ol. was 

### completed in 1997,

### ancl has met V 

### OC Sti!ndards in all**w~lls** 

### since 2002, and PCB. standards .since 

### 2006:. ·Passive removal ofoil inrhe.TI Zone. willcontinue

. on a quart:erly 

### basis, '

### QU~3- Riggs Brook The remedy for Riggs Brook 

### required sediment and biota 

### monitpringin.thebrook•for.aperiod.of.lO years; ...

### Th~smonitp~ing was.<eo!llPleied in
·••• 2005 >vithPCB leve!Sit1 seditnen!.and biota found to 

### bewithin 

### acceptableilimits.• · · Onesrunpiingpo1nL3.0J8,whichhad consistently h<Jdlevels aLor·above the.target



### limitof5 

### ppm; was excavated 

### andrep faced with 

### ctellil soil iiC200K · Il) 

### aecohJ;)ll¢e With the

### Cons~~! Decree, we would like topropose that 

### the pre-certification 

### in$pecti()lJ ht; codducted Ori 

### June29,.20l2:Thefive-year

### revie•v san:Ipling 

### oft.IJ.e.·soil cover• ·



### . .**o~** 

### the Designated ,<\.r.;:a:**litth~** 

### Site 

### bi.' conducted 

### during 

### ilie**~ailles.i1.e** 

### visit. The**s~n·** 

### ·· ·· ··· ·

· ·**.sJtmplin~.will·be** conducted. in .accordance with the 

### Soil Sampling Plan aniiQAPP

### Am~n<!m~!lt,.

## as a**~art** ofthe.2012.five•year review 

### ofthe.Site. ·· ··· · ··· · ··

·· Thank youfor your consideration, and 

### please coritact.irie with any questions.

· ,Sincerely,

· •..... 

### /**//~**

## ~ RD.
. K<"<c•,PJC Project Coordinator



### cc: ClaudiaSait,Maine Q.FP Lori Moreau, Woodard 

### & Curran