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 of the 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 cP AHs over 1 0 ppm, or lead 

over 248 ppm, and consolidation of soils with PCBs and cP AHs between l and 10 

ppm into a "Designated Area". The Designated Area was to be covered with 12 

inches of clean 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 of oil inrhe.TI Zone. will continue 

. 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 be within acceptableilimits .• 

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

limitof5 ppm; was excavated and rep faced with ctellil soil iiC200K · 

Il) aecohJ;)ll¢e With the Cons~~! Decree, we would like to propose 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 you for 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