United States Environmental Protection Agency Office of Emergency end Remedial Response EPA.ROD R06-85.007 June 1985 &EFA Superfund Record of Decision: ------- ,. REPORT NO. EPA/ROD/R06-85/007 (Please read instfuct;'O;'; on ihe'r;;"e~s'e be/o;e completing) 3, RECIPIENT'S ACCESSION NO, \2. SUPERFUND RECORD OF DECISION Triangle Chemical, TX 5, REPORT DATE June 11, 1985 6. PERFORMING ORGANIZATION CODE 4. TITLE AND SUBTI"LE 7. AUTHORCSI B, PERFORMING ORGANIZATION REPORT NO, 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PRDGRAM ELEMENT NO. ". CONTRACT/GRANT NO. 12. SPONSORING AGENCY NAME AND ADDRESS U.S. Environmental Protection 401 M Street, S.W. Washington, D.C. Agency 13. TYPE OF REPORT AND PERIOD COVERED Final ROD Report 14. SPONSORING AGENCY CODE 15. SUPPLEMENTARY NOTES 16. ABSTRACT The Triangle Chemical Company site is a 2.3 acre tract located on Texas. State Highway 87, just north of the Bridge City, Texas city limits. The Triangle Chemical Company operated a chemical mixing and blending facility from the early 1970s until 1981. During the company's operating period, various types of industrial cleaning compounds, automobile brake fluid, windshield washer solvents, hand cleaners, and pesticides were produced. Raw materials and finished products were stored onsite in bulk surface storage tanks and 55-gallon drums. Currently, approximately 51,000 gallons of hazardous materials are stored in 12 above-ground storage tanks. The selected remedial action includes: incineration and deep well injection of the tank and drum contents; decontamination of all onsite structures; offsite disposal of trash and debris; and mechanical aeration of contaminated soils to background levels. Total capital costs for the selected remedial alternative is estimated to be $385,000 with O&M costs approximately $500 per year. . KEY WORDS AND DOCUMENT ANAL.YSIS b.IDENTIFIERS'OPEN ENDED TERMS c. COSA TI Fitld/Gruup 17. a. DESCRIPTORS - Record of Decision Triangle Chemical, TX Contaminated Media: soil Key contaminants: VOCs, toluene 18. DISTRIBUTION STATEMENT 119. S~:nR~ TY CL.ASS ! T/,is RepIJ'1/ 120 SE CU R' T Y CL.ASS , This p~~,,; i None 21. NO, OF PAGES 54 22 PRICE ..- I EPA Form 2220-1 (Ru. 4-77) PREVIOUS ECIT'ON ,5 Oe50L..ETE ".~"'''-' .."'.""..'" '-'.-;", , ------- INSTRUCTIONS 1, REPORT NUMBER Insert Ihe l:.PA reporl number as it appears on the cover of Ihe publkation, LEAVE BLANK 2. 3. RECIPIENTS ACCESSION NUMBER Reserved for use by ~adl r~port rcdpienl, TITLE AND SUBTITLE Title should Indica Ie dearly and briefly Ihe subj~,'1 ,'oVl:rage 1.>1' Ihe r"porl. and lx' d'spla)'nlprumin,'nlly, S,'I sllhlilk. if 11"".1, m "mali,'r Iype or otherwise subordinale it to main lille, When a report is prepar~d in ml.>r,' Ihan ,'n,' vulume, r"l",..llh,' primary lilk. a.ld hllanl<' number and Include subtitle for the specific lille. ' 4. 5. REPORT DATE Each report shall cury a dale indicating at leasl monlh and ycar, Indkall' Ih,' h;asis un whkh ill\as ,,'IC,'lcd (1')[.. JQr,' "J i.mll', ,)QI,' of tlPP'OIItll. diltt of prtptlrtltion. ttc.). PERFORMING ORGANIZATION CODE Leave blank, 6. 7. AUTHOR/SI Give name(s) in ,'onvenlional order (JollII R. DoC', J. Robar /)0(', ('II'.). Lisl aUlhur's al'liliallun if il ,Iiff,'r, frllm III<' l>crfurlllin~ ,.ft:ani. ution. 8. PERFORMING ORGANIZATION REPORT NUMBER Insert if performing organizalion wishes 10 assign Ihis number, 9. PERFORMING ORGANIZATION NAME AND ADDRESS ' Give name, street, ciiy, state, and ZIP cod~. Lisl no more than Iwo levels of an ur~anizaliunal hireardlY. 10. PROGRAM ELEMENT NUMBER Use the program element number under whi.:h Ihe reporl was prcpared. Subordinale nUIIIl>.:r~ mOl)" ~ illl'hhk,lmp;u,'nlh,''''s, 11. CONTRACT/GRANT NUMBER Insert conUact or grant number under which report was prepared. 12. SPONSORING AGENCY NAME AND ADDRESS Include ZIP code. 13. TYPE OF REPORT AND PERIOD COVERED Indicate interim fmal. etc.. and if applicable, dales covered. 14. SPONSORING AGkNCV CODE Insert appropriate code. 15. SUPPLEMENTARV NOTES Enter information not included elsewhere but useful, such as: To be published in, Supersedes, Supplements, etc. 16. ABSTRACT ' Include a brief (200 words or less) factual summary of the mosl sil!nilkitnl Infurmali"n ,'unlaln"" III ,I,,' "'p"fl. II III,' f,'p"rl ,'''II;IIIIS a significant bibliography or literalure survey, menlion it here, Prepared in .uopcratiun with. Iranslallt'" III, 1',,''''"1,''' ;,1 ...'nh''''I1''' III, 17. KEY WORDS AND DOCUMENT ANALYSIS (a) DESCRIPTORS. Select from Ihe Thesaurus of I.nginecrin~ and 5.,.'11111" [Cfms Ihc prupCf aUlllllrll,'J ,,'I Ills Iliallt.knllty II", m;'Jllr concept of the resea,,:h and are sufficiently >pecific and predse to be used as rnJe:\ enille, lur ,alalll~an~. (b) IDENTIFIERS A~D OPf'.!\-I:.NDED TERMS. L'se Idenufieh for prO)ed nam", ,'ude nam~s, "4ulpm"111 j"sl~n;'lors, \'t,' Cst.' "1'.11' ended terms written In deso.:riplor form for those ~ubjects for which no des"lplur c"isIS. (c) COSA TI III,LD GROL'P. Held and group assignments are to be laken frum the I ~65 (,OS.I\'II Suht""t ('al"!!lIry l.i,l, Slno.:,' Ihe ma. jority of document> arc multidisciphnar)' rn nalure, the Primary I ieldi(;foup asslgnmcl1u s) Wlllbc Sl',', ,I", .Ii" Il'hn,'. a"'a III IIlIlIIan endeavor. or Iype of physl.:al object. The applicationls) will be cro>s.rcr'eren.cd wllh scnmoary 11..1".'( .rllup ~"I~IIII"'lIls Ihal "1111011"" the primary postinglsl. ' 18. DISTRIBUTION STATEMENT Denote releasabilil) to the publil: or hl1l1lallOn for reason> uther than s.:.urll~ lur e,\aml"le "I(dl.'as,' 1.1111""1"11." I II,' all' a';lIbh,IoI) III the public, Wllh address and prke. 19.8<20. SECURITY CLASSIFICATION DO NOT submit dassified reports 10 Ih,' :'-iatlOnal Tc.hm.allnformation si:rv..c, 21. NUMBER OF PAGES Insert the 10lal number uf pages, indudanl! Ihi' onl.' and unnumbered pagcs, hul c:\dudc dlStrlbuliun 11'1. ,I ~ny, 22. PRICE Insert Ihe pll.e s~t by the ~ational fc.hm.:al Infofmatlon Savilc ur Ih... Cuvernmcnt I'lIntm!: Olrilc, ,I knll"n, EPA Fo,m 2220-1 (Rev, .-77) (Reve,..) ! .... '''-., ------- RECORD OF DECISION REMEDIAL ALTERNATIVE SELECTION SITE: Triangle Chemical Company, Inc., Texas State Highway 87, Bridge City Texas DOCUMENTS REVIEWED I have reviewed the following documents describing the analysis of cost- effectiveness of remedial alternatives for the Triangle Chemical Company site: - Triangle Chemical Company Site Investigation, Roy F. Weston, Inc., September, 1984 - Triangle Chemical Company Feasibility Study, Roy F. Weston, Inc., Mar~, 1985. ". - Staff summaries and recommendations. DESCRIPTION OF SELECTED REMEDY o Storage tank and drum contents - offsite incineration, deep well injection. o Storage tank sludges - offsite landfill. o Onsite structures - decontaminate and leave onsite. o Trash - offsite landfill. o Contaminated soil - onsite mechanical aeration. DECLARATION Consistent with the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) .and the National Contingency Plan (40 CFR Part JOO), I have determined that the selected remedy for the Triangle Chemical Company site is a cost-effective remedy and provides adequate protection of'public health, welfare and the environment. The State of " Texas has been consulted and agrees wi"ththe approved remedy. In addition, the action will require future operation and maintenance activities to ensure the continued effectiveness of the remedy. These activities will be considered part of the approved action and eligible for Trust Fund monies: ------- '. I have also determined that the action being taken is appropriate when balanced against the availability of Trust fund monies for use at other sites. In addition, offsite destruction of liquids and secure disposition of solids is more cost-effective than other remedial action and is necess~ry to protect public health, welfare or the environment. L II. 17rJ (/ DA TI; '.., . ------- SUMMARY OF REMEDIAL ALTERNATIVE SELECTION TRIANGLE CHEMICAL COMPANY BRIDGE CITY, TEXAS ". .~"" . ------- TABLE OF CONTENTS Site Location and Description 1 1 3 5 ~.. . 6 . 7 16 17 18 Site History Current Site Status Migration Pathways Enforcement Analysis Alternatives Evaluation Community Relations Consisting with Other Environmental Laws Recommended Alternative ------- t RECORD OF DECISION REMEDIAL ALTERNATIVE SELECTION TRIANGLE CHEMICAL COMPANY BRIDGE CITY, TEXAS Site Location and Description The Triangle Chemical Company site is a 2.3 acre tract located on Texas State Highway 87, approximately one-half mile north of its junction with State Highway 62 just north of the Bridge City, Texas city limits as shown in Figure 1. The site is bound on the north by a commercial property, on the south by a residence, on the east by Highway 87, and on the west bY Coon Bayou, in an area that is projected to become increasingly urbani zea' in the next decade (Figure 2). The population of Bridge City is approximately 10,000 people. There are 15 houses and 50 mobile homes within -1/4 mile of the Triangle Chemical site. Natural grade elevations at the site range from four to seven feet above mean sea level. The site is located in the l00-year floodplain as identified by the Federal Emergency Management Agency. However, the combination of frequently intense rainfall, gentle site slope, and poor drainage and tidal influences in the bayou system, which discharges into the Sabine River approximately three miles downstream, has resulted in inundation of the site once every 6 years. . Groundwater is a major part of the public and industrial water supply in the region and is furnished by the Chicot and Evangeline aquifers, which are hydrologically connected and considered a single unit called the Gulf Coast aquifer. The shallow water table normally lies about 6 feet below the ground surface. However, during periods of heavy rain the water table has risen to as high as 2 feet below the surface. The site surface includes five ~uildings and thirty tanks, as seen in Figures 3 and 4. Twelve of the tanks currently contain hazardous liquids totalling 51,000 gallon5. The buildings were used for office space, processing areas, and loading areas. , Site History The Triangle Chemical Company operated a chemical mixing and blending facility from the early 1970's to 1981. During the company's operating period various types of industrial cleaning compounds, automobile brake fluid, windshield washer solvents, hand cleaners, and pesticides were produced. Raw materials and finished products were stored in bulk surface ------- , " , , .. " . ./ ".... , ~ c . .)'",~.., . . '.'~. l -.- / cr . "..!..~,t .. o ,-'-V " . . ,. ..... .. ,"" ..... .." .,. . , . - -...., FIGURE 1 SITE VICINITY t~AP ~ --......."-: ------- i \ LEGEND I .0 SCALE I a MILES I I I I 1/2. . ) I ~ ) t - Urban Agriculture Forest Wetlands Rangeland Water ---'''''- FIGURE 2 PROJECTED REGIOtIAL LAt!D USE 1995 I JURCE: AREAWIDE WASTE TREATMENTJ! MANAGEMENT PLAN SOUTHEAST TEXAS AREA I'~ I TRIANGLE CHEMICAL COMPANY I 4 I 8 ~ t I . , ------- APPROX81ATE 'ROPERTY L- . I . I . / / . . I . I .;,'. .. LOADING DOCK PROCESS ..LOING 00 00 ~. 00 IItOUSIARD r WICS 0 00 PROPERTY 0 ~~S REDIIRD CHEMICAL OFFICE I LAI ITATE MIIHWAY .7 . FIGURE 3 TRIANGLE CHE~ICAL C~PANY ------- INSIDE PROCESS BUILDING r: PI4 ..13 '12 - BROUSSARD PROPERTY rip& 0/'4 P3 P2 '1 COON 8AYOU INLET A4 A3 AI AI "'.A. '. -RED 81 RD CHEMICAL \ I i I \ . \ \ I I \ STATE HI8HWA" a7 ..-.- LeGeND B EMPTY TANK tl TANK CONTAINING LIQUIDS ~. Fi qure 4 LOCATION OF PROCESI . AND STORAGE TANKS ------- 2 During the latter period of plant operation, numerous fish kills in Coon Bayou were reported by the local residents. Documented fish kills near the site are listed in Table 1. Subsequent investigations by the Texas Department of Water Resources (TDWR) indicated that these fish kills could have been the result of discharges of hazardous materials from the site. . In August 1981, TDWR acquired a temporary injunction against Triangle Chemical Company, calling for compliance with pollution control laws and prevention of further untreated discharges from the site. In October 1981, TDWR found the site to be abandoned. Limited sampling of drums, spill areas, runoff areas, and Coon Bayou documented that hazardous materials were located onsite and were migrating offsite via stonmwater runoff and direct discharge reinforcing the possibility that the fish kills could have been caused by hazardous material spills from the site. The drums stored onsite were noted to be in a deteriorated condition with some bulging and leaking. ~. . After the Trustee in bankruptcy for the Triangle Chemical Company i~dicated that the cOmpany assets were insufficient to perform any necessary cleanup work at the site, the Environmental Protection Agency (EPA) initiated an Immediate Removal Action under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) to deter public access to hazardous' materials on the site in April 1982. This action consisted of: (1) building a six-foot high chain link and barbed wire fence around the material storage area, (2) posting warning signs around the site, and (3) constructing a drainage canal in front of the main drum storage area to prevent runoff from reaching Highway 87. The cost of this action was $8,082.25. In August 1982, a Planned Removal Action was conducted to remove the drums and contaminated debris at the site. Under this action, the drums were' staged and liquids were pumped to bulk transport trucks for offsite disposal. Empty drums were crushed and removed from the site along with contaminated trash and soil. The soil removal operations were limited to the drum staging and crushing area. The wastes removed from the site during this action were taken to an approved hazardous waste disposal site owned by Chemical Waste Management, Inc. in Port Arthur, Texas and included: 21,000 gallons of liquid, 350 cubic yards of contaminated soil and trash, and 1,095 55-gallon drums. The cost of this action was $74,755.25. In July 1982, -TDWR nominated the Triangle Chemical Company for inclusion on the National Priorities List. The site ranked high enough to be placed on the list and bec.ame eligible for remedial investigation/feasibility study (RI/FS) funding. In August 1983, a cooperative agreement between EPA and the State of Texas was approved, awarding $183,000 to conduct the studies. Roy F. Weston, Inc. of Houston, Texas was selected to conduct the RI/FS. The onsite activities for the remedial investigation were completed in April 1984 and the final report was received in September 1984. The ------- TABLE 1 DOCUMENTED FISH KILLS ON COON BAYOU DATE LOCATION CAUSE NO. FISH KILLED 03/27/76 Near SH 62 & Winfree Rd. Low D.O. No Count 09/06/77 Near Confluence of Cow Low D.O. 10,000 Bayou 10/24/77 Private Pond Adjacent to Low D.O. 1,250 Coon Bayou & Hoo Hoo Rd. .~. 03/25/78 Between US 87 and Mouth Low D.O. 1 ,000. of Coon Bayou . 05/05/78 Between US 87 and Mouth Low D.O. 38 of Coon Bayou 11 /2/81 Near Hoo Hoo Rd. Bridge Low D.O. No Count 10/19/82 Private Pond 1 Mile Low D.O. No Count Upstream From Plant ------- 3 In response to suspected unauthorized activities on the Triangle property, a third emergency action was undertaken to completely enclose the site with a six-foot chain link fence in March 1985. Current Site Status The site investigation performed at the Triangle Chemical Company generated substantial information concerning the regional geology, site geology and ~drogeology, and site geochemistry. Regional stratigraphic information is presented in Table 2. Bridge City and Orange County are located in the southernmost surface exposure of the Beaumont Clay Formation, consisting primarily of interdistributary muds and distributary sands and silts of the Pleistocene Age. As seen in Figure 5, the soils at the site consist primarily of silty clays of the formation. The uppermost stratum is a dark brown, clayey silt containing some organics fiber, representing a weathered soil horizon of the Beaumont formation. Underlying the clayey silt is a silty clay containing trace fine sands. This soil layer was found to be stiff and moist during the site" investigation. Within the silty clay unit are lenses of light brown silt containing traces. of clay and very fine sand. This silt is typically saturated and soft, varying in thickness from 2 feet to 5 feet across the site. Adjacent to Coon Bayou, a light gray silty clay was identified underlain by a black silty clay containing a significant amount of organic fiber. .. Groundwater elevations, monitored during the site investigation, indicate that shallow groundwater occurs across the site at depths of 2 to 6 feet below the surface. Fluctuations in the shallow water table elevation are associated with local weather conditions. During periods of heavy rainfall, the water table has been identified as high as 2 feet below the surface. Based on measured groundwater elevations, horizontal groundwater flow occurs in a northeasterly direction across the si te and di scharges into Coon Bayou. The influence of tidal variations on the water table elevation is not significant enough to effect overall groundwater flow. . As seen in Table 3, the onsite shallow groundwater is slightly contaminated. Because the ma«imum contaminant concentrations are well below the concentrations established by the National Drinking Water Standards and the Clean Water Act water quality criteria (Table 4 and 5, respectively), the groundwater does-not present a significant threat to human health and the. environment. It should be noted that the shallow groundwater is presently subject to future contamination from leaching of contaminants due to an elevated water table during severe rainfall events. The site is located immediately adjacent to Coon Bayou, which is a tributary 01 the Cow Bayou and Sabine River drainage systems. There are no stream gauging stations in Coon Bayou, however, flow variability in Coon Bayou is similar to the variability of Cow Bayou, in which the flow ranges from 0 to 4,600 cubic feet per second (cfs), with a~ average of 101 cfs. Both bodies of water are influenced by tidal fluctuations; extremely high tides have, ------- 'TABLE 2 STRATIGRAPHY OF THE TEXAS GULF COAST REGIO~ - f.re I,...... 5rrl.. "rell...phlc '''III ,,'~.....I..t~ ""It. 'd.c." '_I ...,..... I--.h - . -.--- .--..-.-- Ai 1-;;1;';''-- -. . ---:-~'I~ .. :-~~~-jj"~i._- :0: i:: .....,.." 'J.t.. ,",.11""'" .. .. "..1.'.....'" .-!''!''.C'~9J....r.!8!!.lCIII dlleo. ....Un ...1.'." .. ..,.tl.'n-. ~o: .~"!..!~..., 1- .-.--- --.- 11111.. 5.'" . --.... t'1I........ Cu II" .... 1.....11- ....Un ..II.' .... .....,1.,...' .... ,.. -....- La.... c:o.ah. ~ ....... r-. t.. ",........."', """'f'" c..U.I,. lit................".......,..... .......... -----=: "'f"""'"'' .......... -.;.- ''''''''.tI.f''''' .,. 0810.111. 5.".'''' 1...1..""" 0810.111. ......- rI_l,. r...-II- .... ,., W..hl,..oe c:o.a.,. "1-- 5 ......' ,... 0' J..,.. ...1 f.r . C.'.'_II. 'u" I Coo......I. '.If h or s....'- Coo......I. '.ff ".1_'"'' .. " . .. ......- . ,....,,,.... ............. 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""""" ... olin...'" .... oiIoow ,...... ...10 Oll-.oco. I. ..~. .. _~!'!!.!."'L.r;!.,-. -.- .. ..,d.olollr ...1.. ............ !;....h.- 10 ..... ...por t . "., I....... """"""," Ioc... ...- _-~I~lO~;!-';~}!~-- .J!,!!..!!.!!--~!!!!!! - Nt""""'''' .... .. ,..."....;. e c: I:,~~.!'!'-' ~ J!!.!.!!!!!!!.L"!!.- ,....tM"". ....,....'n'.' j ~ ;;,!'!.!_:i-..!--- - ',......."" ,".ft'.. ...;. ... : .~=~~.!.!'~~!!'." . ",..,.-,..'_,,,,, ..,...... ~" .."'!"'-:~. .!:t' f. ~j~~~ U Jr. taw ,......, ,... I '-- ~~ !!i!! ii :.~r._::.._. ' ....1_- '!! !!,!!.~r!!!L.. !. -- ". *!!.!i!"9- . 1 , ~ .,,'; .), . . '::..::d ------- orra...... , 118' lse PROCDI-- SIll I IILn CLAyeCL) IUCIC OMANIC -3 IlL TV CUy eCl) -,- , I CUftY8LT ;----T~ I ..n CLAY 8IL-CL) I .. I aT -.J I I I " , ------' . I I t , I t I an CLAYCCL) I -IS .L .L FI~UP.F. 5 SITE GEOLOGY .~.- - .. U.IIID .: T ..OUIID I...'ACI DIPTH 0' WILL CAI... .. .011.. .L UNTH 0' WILL ICIII.II . la. PACK -%- WATIII n.LI'. .- lUll' ...-zeIIf1&.. .-.- VlItTICAl . r. ~ - OIOLOOIC.COIITACT - t- ,. 1IIC COWTaCT ,,",.111110) IU.I.'ACI CIIOII ------- 'BLE 3 TRIANI., JE!t1ICAL COt1PArlY ANALYTICAL PESULTS GROUNDWATERS dMlDD "IT ~ "I ..'D ... --- --, PI"" ... U8:0''''~ CDD!IfIM11III -.u. I .u. 1-""'10''111 ..... I _.I. .-1Itft.1OIft .u.1 lUll( IUI8 L"T """18 ../I lIP .. .. .. .. .IIS .. 7.' 7.1 1.1 1.1 0..1- ../I " lIP .. .. .11 ower ..'I lIP .. .11 " .1' ..... ../I lIP lIP .. .. .11 _Id.' ..'I lIP lIP .11 lIP .11 SUnr ../I lIP .. .. .. .11 ZIIIe ..'.1 .15 .11 .II " 'IS 10: .." 75.' 51.1 31.1 11.1 ..1 ..1 IlpeeU'e 0iIIIdIIe'- . ...,. ..111 '" ... I..S - .." lIP lIP '.1. oua or--I.'r." "" lIP .. I... 011 a Or...........,I, ../l .. 1.1 "I. III !'OU.... "Ialll... .....,.- OIl.''''' .." II II II II n. II "I.II~ "U'~!!!.!!!8 ...!!!.!! DI-.~.,I "'hlla'. .." 51 lIP lIP " II ... (t-I''''' ""1) "''''a'8 .." $I lIP .. .. II "'.Itt. "U".I ""!eldn Della-III: ../I .,- . ~!~.., ~Ua!!!'t !!Id ~!~~~!~It! ,"....".......... .." 11-28 .. u II :.: ...1 al.. ... _-,..'.11, pa"a'.' ..lalli, ,....... ...,1- 0' .Icaa ''''Iea... 1."- 10 lie .-_._1. ~I_I.I, II ../I. .1 .. t.JM8lul la _1,lIcal ...,.11- ,....... ; J .J :. .\~ "."' '.., ------- TABLE 4 U.S. EPA DRINKING WATER STANDARDS STANDARD CONSTITUENT MAXIMUM CONCENTRATION 119/1 Primary Drinking Water Secondary Drinking Water Arsenic Barium Cadmium Chromium Fluoride Lead Mercury Nitrate (as N) Selenium Silver Endrin Lindane Methoxychlor Toxaphene 2,4-0 2,4,5-TP Silvex Chloride Color Copper Corrosivity Foaming Agents Iron Manganese Odor 0.05 1.0 0.01 0.05. 1.4 .: 2.4 0.05 0.002 10 0.01 0.05 0.0002 0.004 0.1 0.005 0.1 0.01 .;.. .. 250 15 color units 1 Noncorrosive 0.5 0.3 0.05 3 Threshold Odor Number 6.5 - 8.5 250 500 pH Sulfate Total Dissolved Soli4s (TDS) Zinc 5 References: 40 CFR Parts 141 and 143. ------- Compound* Diethylphthalate Di-n-Butyl Phthalate Pentachlorophenol TABLE 5 CLEAN WATER ACT WATER QUALITY CRITERIA Water Quality Criteria Fish and Drinking Water Water Quality Criteria Drinking Water Only 350 mg/l 34 mgl1 434 mg/1 44. mgl1 1.01 mgH.,. 1.01 mgl1 * Volatile organic compounds detected at Triangle Chemical Compa~y . ------- 4 Data generated during the site investigation, presented in Table 6, shows that the surface water directly adjacent to the site is only slightly contaminated. Concentrations of contaminants detected are well below drinking water and Clean Water Act water quality standards. Therefore, . contamination of surface waters from the site is not considered to be si gni fi cant. During the site investigation, several 55-gallon drums of chemical product were observed in a building on property owned by the Triangle Chemical Company, north of Redbird Chemical Company. These drums are in deteriorated condition, and pose a threat to human health due to direct contact with the public. Therefore, disposal of these drums is addressed as part of the remedial action at the site. The results of the site investigation and supplemental sampling perfonme~.. during the feasibility study indicate that approximately 51,000 gallons of hazardous materials are stored in 12 above ground storage tanks onsite. The analytical results of samples taken from these tanks are presented in Tables 7 and 8. The results of the site investigation also indicate that soil contamination is restricted to past drum and tank storage areas onsite. Concentrations of metals detected are within the range of levels found to occur naturally in the soil in the area. Onsite soil contamination is extensive for volatile organics compounds (VOC), as seen in Figure 6, which illustrates the lateral and vertical extent of soil contamination of greater than 500 parts per million total volatile organics. Concentrations of' specific volatile compounds found in the soil are listed in Table 9. A total of 1,990 cubic yards of contaminated soils are onsite; no contaminated soils were detected offsite. .. The following conclusions were developed from the remedial investigation: o Near surface soils on the site have been contaminated from migration of the waste materials through spills and leaks from drums and tanks. o Groundwaters below the site are not significantly impacted by the fac.n i ty. o Surface waters in the vicinity of the site are not significantly impacted. . o Air quality at the site has not been measurably impacted. o Tanks containing hazardous materials remain unsecured onsite. o A large quantity of general refuse, a portion of which is potentially contaminated with chemical product, remains onsite. o A drum storage area on Triangle Chemical Company's northern property remains unsecured. ------- TABLE l TPIANr,lE cHEtncAl COf1PAtlY A~AlYTICAl RESUrTS SURFACE ~JATERS aMUtk40 II" T OF B-IW B-IW-D fiElD DETICI'ION CDtCOO'RATION INLET INLET DIPLIQ\TE 8Lt\NK LIMIT Pheno t s ~/I NF .005 pH ~/I 6.2 7.2 7.0 Chrami um ~/I NF NF .05 Copper ~/I 0.19 .03 Lead ny/I NF NF .5 Niekel ~/I NF NF .l Si her ~/I NF NF .l Zine ~/I 0.04 NF .02 P!ior~ ty~!!uta!!t B8s~J.~u.!~!J! Di-n-Butyl Phthalate ug/l 22 38 13 10 Diethyl Phthalate ug/l NF NF 13 10 1. ------- TABLE 7 ANALYTICAL RESULTS OF TANK SAMPLING DUPING EMERGENCY RESPONSE ACTION . . AUGUST. 1982 tANR NUMBER COM POUN D* A2 A3 A4 13 14 21** TrichloroethyleDe 2,351 16,000 69 1,1,2-TrichloroethaDe 13 401 laDzeDe 10 52 72 1,1,2,2-TetrachloroetheDe 39 550 TolueDe 620 733 412 3,400 711 lfapthaleDe 1,112 4 6 ,28s'.~' 58 Ethyl leDune 132 77 . 20,000 82 2-lthylhezyl Phthalate 220,000 309 1,2-DichloroethaDe 710 2-CbloroethylviDyl Ether .. 2,000 l,4-DichlorobeDzene 5,561 1,2-DichlorobeDzeDe 43,500 If-NitrolodipheDylamine 218 800 PCB (polychloriDated biphenyll) 75 Chromium 0.15 0.02 150 0.04 Copper . 11 0.35 4.0 0.07 5.8 0.42 Laid 2.5 1.0 0.09 7.1 0.3 . Bickel 0.5 0.2 0.03 1.3 0.3 0.06 Silver 0.2 Zinc 12.9 0.5 1.1 0.4 0.09 Mercury 0.003 * All concentrations of organic compounds expressed as parts per billion (p~b) All concentrations of inorganic comDounds (metals) expressed as parts per billion (ppb) ------- : 8 TRIANGLE ~rtEMICAL COMPANY ANALYTICAL RESULTS OH TANK CONTE~ITS ... fII ~ .......-.~.. 11 U II . " " II fU 81 15 . "",dalal'1~ -.11 .. I.U2 .. .. .. .. .. .. .. .. .. """"18 ....In -.I1 ' .r .. .. " " " " " " " " ........ ..Ii .r .. .. .. " " " " " " " ~ l1li1 .r .. .. .. .. .. .. .. .. .. .. ~~.. 8II1 .r .. .. .. " " " " " " " 2.H 1III1 .r .. .. .. " " " " " " " 2..,5-9 1III1 .r .. .. I.on " .. .. .. .. .. .. ~J"'- Op 181 " " 100 125 1]1 .. 181 .. 115 110 I88II:t1wlty ..' .. .. .. .. .. .. .. .. .. .. .. 1.1 '.2 11.2 11.1 .,.. . .,... aI. lI.t t.' 1.1 '.0 An8Ie ..,. .. IF 0.011 0.013 II:Jft 5 1.011 1.021 1.11' I.DOt .. IUI'I 5 _1- l1li1 " " " " 10ft 5 .. I." .... .. .. IUI'I 5 . Q8II- ..,. .. .. .. 0.. 10ft 5 " .. " .. .. 10ft 5 CIIn8I- l1li1 I.. 1.1. .. ".0 11M 5 0.15 '.15 '.15 .. '.21 11M 5 .... l1li1 1.. J.' I.D 2.' 11M 5 0.' 1.. J.2 .. 1.. IUI'I 5 ....., l1li1 "" .... .. IIJI8 . 10ft 5 " .. '.D5 .. IUI'I . IIJI'I . 181-- l1li1 " " " " 10ft 5 .. 1.18 " .. .. IIJI'I 5 811.. l1li1 " " " " 10ft . 0.1 .. '.1 .. .. IIJI'I 5 ........t8 l1li1 .,- 92 .. 100 II:Jft . .,.. . .,... .. ..- " - o.bu....u. l1li1 J,.. I 1.- t,2IOO II:Jft . 10ft . lUll. 13,- 2." 100 1... IIIIIIII8 . .. .. .. 0.01 O.U 0.1' 0.01 .. .. .. .. CblCII'III8 . O.OJ " " 0.21 0.02 .. 0.01 .. .. .. .. Mal QrtIa . 13.. J.]] 1.'71 20.. I] 17.' 1." 0.'1 2.. ..57 .... .1"P"'8 . 0.01 " " 0.21 0.02 .. 0.01 .. .. .. .. ~~. . 10.' U.7 U.O 10.6 11.' 11.' 10.7 ,i. 10.' 11.0 10.2 10.1 .ltI'GIIB . 0.11 " 1.1). 0.11 .. .. O.U .. .. I.U .. AlII . 1.10 " 0.02 1.] .. 0..' 1.1 1.1 0.10 0.10 0.. " ". ------- TABLE 8 (CONT.) TRIANGLE CHEMICAL COMPANY ANALYTICAL RESULTS ON TA~K CONTENTS .... f1I -..:.. v- -___~ .M AI AI II II ., II IV D . . --.atr . -': 08t' r- L 1.8 1.5 I.t ..0 1.5 1.1 2.. I.t 1.1 1.5 1.' ...,.. -.&.. 1.- ..- 1.- 1.0]9 ...U I... 1.- 1.- 1.1159 1.- 1.- IIWIIt .. .. .. .. 11.- It... .. . .. .. .. r - a a 811* 8IIl 12 U J7 . 2.110' .., S 111 12 " t """"tr ... ... '.17 '.11 1.11 '.1. .. .. .. '.11 '.12 .... 1 ""'" a ...... DU. 1D2. DII. ... lIM. 181. 111. I... tI ...... ua J ....,. tIIIIIeItr """,,'~ ._)1-'''''' --.... ..... t88 .... U - faIIII to -"'.8111 .... ...,. IIIID. U..,. II1II'. .'.......... -.. ....- "-..., ........................... S """""'''-'''''''"""".",,,,,-,,,-toe....at'''''',, J - 1 j. 1IIIU8r,.. -- ... ........ .au. 18k!tI..., ....... --...,.... -~ 8Itdc ... ... ,... .u8Ct1an t8:ll1I...- ... -t8IIUI. lilt ... -* ......... .-...A. ..Uty GIIIIItI'CIi f8ta. . .... ., ..... I ...... ....... ..... ..........'" . - t ...-"M18 ~ Wit...AI t"", ...,... , .... ., ..... ..... -- fD8 fl1- .. dI881w. 81181"", -* .. ~. , , . Ii> j . i ------- .d . . .' 9AOtJSSo\AO F'-~ ,1.7 , CHA" \.... F£NC£ '\ -- .-,.-.-.--.-. HOM( , OFFIC£ ,.. .D ~ .. ~ I: ., i ... ~ ... 'It I :1 . ~-- L ~ ......--. .. / --,--- '--'-1--" -- -- i'AQP[R ry LOADING BUILDING PAOCfSS IIJILDItG NO S L : \.j::1G DOCK LOA~ DOCie RA'" 0000 0000 AEIIIIIAD Ql[MI:Al. PWOPERTY PPOCE5S ,iI,ILC:'4G :'0.1 PAOC£SS 1UL00NG NO.2 ..~...~.."" t.""..~""" J. -=- , . . .. , " rAlo\,.;t. E Ct4EMlCAL I PftOPf.RTY UN( ICM.r,r.40' Fiaure 6 LOCAnOIl 0" .O'L 80..IIQSI SOIL ZONES WITH TOTAL Y.O.C. ------- TABLE 9 TRIANGLE CHEMICAL COMPANY ANALYTICAL RESULTS SOILS 1 ' 55-4 SURFACE SS-4 DETECTION . NATURALS IN SOILS COMPOUND UNIT OF CONCENTRATION SC-l SURF ACE. SC-l SC-2 SC-2 1 ' SURFACE 1 . SC-3 SURFACE SC-3 1 ' SC-4 SURFACE SC-4 1 ' LIMIT AVE. RANGE Phenols ug/gm NF NF NF NF NF 0.233 NF 0.051 0.086 NF .005 pH SU 8.1 7.7 8.3 7.9 8.3 8.3 8.1 7.6 7.6 7.0 ChrOOlium mg/kg 4.8 5.0 3.0 4.4 12.1 7.2 7.5 12.4 4.9 3.4 .05 200 5-1.000 Copper mg/kg 11. 5 10.0 7.2 7.6 14.1 10.7 8.5 10.2 9.1 5.2 .03 20 2-100 Lead mg/kg 57.2 19.5 36.6 49.2 89.3 22.1 23.0 27.1 43.4 15.7 .5 10 2-200 Nickel mg/kg 4.2 2.2 4.2 2.0 5.7 NF 4.9 6.3 NF NF .1 40 5-500 S 11 ver mg/kg NF NF NF NF NF NF NF NF NF NF .1 Zinc mg/kg 102 28.0 28.1 64.1 65.1 232 35.2 11.6 26.3 3.2 .02 SO 10-300 Prioritv Pollutant Base Neutrals Di~-Butyl- Phthalate ug/mg NF NF NF NF NF NF NF 23 NF NF 10 . As per .Chemical Monitoring of Soils for Environmental Quality and Animal and Human Health". Dale E. Baker and Leon Chesmin. contribution to journal series of Agricultural Experiment Station. Page retyped for NTIS - September 5, 1985 . : I ":.';" ------- TABLE 9 (continued) TRIANGLE CHEMICAL COHPANY ANALYTICAL RESULTS VOLATILE ORGANICS IN SOILS COHPOUND. NW-2A SS-SA SS-9A SS-11C SS-l1C SS-l1C SS-12A SS-14A SS-14B REDBIRD 24. 14. 24" 6" 16" 32" 30. 18" 30" 24" TRIP BLANK LAB BLANK Priority Pollutant Volatiles Chlorobenzene NF NF NF NF 0.62 NF NF NF NF NF NF NF 1,2 Trans Dichloroethylene NF NF NF NF 0.13 NF NF NF NF NF NF NF Ethyl benzene NF NF NF NF NF 0.18 NF NF NF NF NF NF Non-Priority Pollutant Volatiles.. Acetone 0.15 0.16 1.4 0.06 0.09 0.05 0.05 0.03 Carbon Disulfide 0.12 0.21 0.22 > 0.05 > 0.04 0.05 Furan Tetrahydrofuran 0.07 0.11 0.04 0.04 Aldehyde C4 0.32 Methylketone C4 0.41 Aldehyde C5 -- 0.04 Hethylketone C5 0.09 0.12 9.7 0.04 Dioxane 0.26 0.22 0.04 Hethylketone C, 2.4 Methylketone C7 22.0 Total Alcohol) C5 1.3 Methylketone C. 0.68 Alkylbenzenes)C. > 3.9 Hydrocarbons C. Total Acetates 0.33 Dichlorobenzene 0.11 0.04 Detection Limit - 0.1 ~/g . An units in)0L9/g .. Concentrations reported are to be used as semi-quantification only ------- 5 The following target receptors were identified in the remedial investigation: o Materials released onto the ground surface from the storage tanks would either percolate into the soil or flow into Coon Bayou. The risk to receptors via surface water migration has been documented by fish k~lls caused by past releases of similar materials that were stored in 55-gallon drums which were disposed of during a removal action in August 1982. o A sudden release of materials in the tanks would also present a risk to persons living and working in the area and driving past the site due to volatile organics released to the atmosphere and direct contact with contaminated soil. o The volatile organic compounds detected in the soils. several of which are suspected mutagens. teratogens. and carcinogens. could be released to the atmosphere during future development of the site affecting worker health and safety. Toxicity. characteristics and routes of exposure for the volatile organic compounds found in the soil and tanks are listed in Table 10. .;.. " No significant migration of airborne contaminants onsite was detected during the remedial investigation. Migration Pathways Groundwater The Triangle Chemical Company site is underlain by the Beaumont Formation, . one of five formations that make up the Chi cot Aquifer of the Texas Gulf Coast. The Chicot Aquifer is the youngest aquifer in the coastal plain of Texas and includes the Willis Sand. Bentley Formation, Montgomery Formation. Beaumont Clay and Recent Alluvium. Recharge to the lower portions of the Chicot Aquifer occur at outcrop~ of the Willis. Bentley and Montgomery Formations, north of Orange County. The Willis Sand consists principally of reddish sands and gravel, silt and clay. The Willis Sand is not known to yield fresh~ater to wells in Orange County and contains slightly to moderately saline water. The Bentley and Montgomery Formations consist of a basal gravelly.sand grading upward into finer sand, silt and cl~. Much of the sediments of these formations are similar to the Willis Sand from which they were at least partly derived. The deltaic coastwise plain of the Beaumont Clay forms the land surface of all of Orange County except along rivers and the coast where it is covered by Recent Alluvium. Much of the surface exposure of the Beaumont Clay in " the northern part of the County is covered by fine sandy 101m because of a greater proportion of sand near the base of the formation. Southward the Beaumont becomes progressively more clayey. While the Beaumont is generally described as consisting of clay it contains much sandy material which can be locally utilized for water supply. Sand beds in the Beaumont Clay yield freshwater to domestic and livestock wells in Orange County. " .. ~ .'";1""'.!'"- ------- TABLE 10 TOXICITY DATA FOR SELECTED ORGANICS FOUND IN SOILS AND TANKS AT TRIANGLE CHEHICAL COHPANY ROUTE OF EXPOSURE TOXICITY CHARACTERISTICS4 SKIN CARCINOGEN MUTAGEN TERATOGEN INHALATION ABSORPTION INGESTION SKIN/EYE CONTACT sans Acetone X X X X X Carbon Disulfide X X X X X X Chlorobenzene X X X X X Dichlorobenzene X X X X 1.2-Dichloroelhylene X X X Dioxane X X X X X X Ethyl Benzene X X X X X Furan X X X X X X Tetrahydrofuran X X X X X IAtfKS Benzene X X X X X X X Dichlorobenzene X X X X X Dichloroethane X X X X Ethyl benzene X X X X X . Napthalene X X X X X l,l.2.2-Tetrachloroethane X X X X X X Toluene X X X X X X l,l.2-Trichloroethane X X X X X Trichloroethylene X X X X X X ------- 6 The recent alluvium in bayous supplies small quantities of groundwater to temporary residences. Although the alluvium is capable of furnishing large quantities of groundwater, large scale development would induce or accelerate movement of saline water from the rivers into the aquifer, eliminating th~ potential for using the aquifer as a major resource. As previously discussed, shallow groundwater is encountered between 2 and 6 feet below the surface of the site. Fluctuations in the shallow water table occur primarily due to local weather conditions, rising during periods of heavy rainfall and falling during drier periods. Although a tidal influence is seen in the water table, fluctuations due to this influence are not significant. The remedial investigation confirmed minor contamination of the shallow groundwater. The fluctuations in the water table and heavy rainfalls . associated with these fluctuations indicate that the observed groundwater" contamination is due to periodic leaching of soils when the water tJble has risen. Based on the observed contamination, soil permeability (10-3 em/see), and direction of flow, it is possible that soil contaminants leached into the groundwater could impact Coon Bayou. Surface Water Surface water has been contaminated from the site from runoff during flood events and from leaking tanks and drums. Seventy-five percent of the site lies in the lOO-year floodplain as designated by the Federal Emergency Management Agency, and portions of the site have been inundated at least once every six years. Potential exists for future contamination of surface water due to erosion and transport of contaminated soil and a release of . contents from deteriorating onsite storage tanks. Air Results of the remedial investigation indicate that air quality in the area has not been adversely affected by the site. Volatile organic compounds were released from the soil surface after spills from tanks and drums on the site, but no contaminants were detected in the soil within one foot of the surface. Volatile organics were detected in soils 1 to 5 feet deep in concentrations as high as 500 ppm, and could be released suddenly during future site development. It is unlikely, however, that significant air quality degradaton will OCCur if the site surface remains undisturbed. Enforcement Potentially responsible parties (PRPs) for Triangle consist of the Triangle Estate which is currently in Chapter 7 Bankruptcy; approximately six companies and corporations that have either owned Traingle Chemical or were sister companies of Triangle operating from the same location; and officers of the companies and corporations associated with Triangle. None of the companies involved are solvent. . .-.-.. .'-";.""'~"'''''''''..'''''~''' ------- 7 The State of Texas obtained an injunction against Triangle in August of 1981. This injunction required Triangle to comply with all pertinent rules and regulations. At the time of this injunction, Triangle was operating under Chapter 11 Bankruptcy rules. Approximately two months after the. injunction, the Texas Department of Water Resources (TDWR) discovered that the facility had been abandoned. In August 1982, EPA Region VI forwarded a cost recovery case development plan to Headquarters. This CERCLA cost recovery action was for monies expended in the emergency and planned removal actions begun in April 1982, and continuing through August 1982. This cost recovery action is pending in the bankruptcy court. . Due to the insolvency of the entities involved with Triangle, remedial action could not be obtained in a timely fashion through litigation. However, PRPs will be offered the opportunity to voluntarily implement .;.:... the selected remedy. Alternatives Evaluation The feasibility study for the Triangle Chemical site was perfonmed to detenmine what actions, if any, would be appropriate as part of a penmanent remedy for the site. Several alternative remedial methods were developed to cost-effectively mitigate damage to, and provide adequate protection of public health, welfare and the environment from past and future releases of contaminants in storage tanks and soil currently onsite. . . . The National Contingency Plan. 40 CFR Part 300.68 (e) (2) states that "Source control remedial actions may be appropriate if a substantial concentration of hazardous substances remains at or near the area where they were originally located and inadequate barriers exist to retard migration of substances into the environment.M In accordance with the plan, and based on the conclusions of the remedial investigation, a source control remedial action is necessary at the Triangle Chemical site. The major threats to public health and the environment attributed to contaminants at the site are: . . 1. Direct c~ntaminat1on of groundwater 2. Rupture of storage tanks, releasing contaminants to the soil. surface water. and atmosphere. 3. Uncontrolled releases of volatile organic contaminants in the subsurface soils resulting from future developmental excavation. Remedial Objectives The feasibility study performed by Roy F. Weston Associates in March 1985 developed the following objectives based on the results of the remedial investigation: o Remove and dispose of the contents of the storage tanks in an approved disposal facility. and decontaminate the tanks. ------- 8 o Prevent significant degradation of the shallow groundwater. o Prevent significant degradation of surface water. o Reduce contamination in the soil to mitigate future impacts on human health. the environment. and site development. o Remove and dispose of the trash in and around the buildings onsi te. At the time the facility was abandoned. 1.095 55-gallon drums used for storing raw materials and products were located on the site. Therefore. closure of the site must be in compliance with the Resource Conservation and Recovery Act (RCRA) 40 C~R 264.178. which states that "at closure. all hazardous wastes and hazardous waste residues must be removed from the containment system. Remaining containers. 1 iners. bases and sol1 contaij'l1.ng or contaminated with hazardous wastes or hazardous waste residues must be decontaminated or removed." The Permit Applicant's Guidance Manual for Hazardous Waste Land Treatment. Storage. and D1sposal Fac111t1es states that. at closure of a fac11ity. s011s are considered to be decontaminated when the concentrations of hazardous constituents are at background levels - for soil in the area. Criteria to measure the accomplishment of the objectives developed for the contaminated soil were established based on time-weighted average permissible exposure limits (TWA-PEL) and short term exposure limits (STEL) for volatile organic compounds identified in the soils and regulatory requ1rements for the closure of container storage facilities. These TWA-PEL's and STEL's are listed in Table 11. Appropriate levels of soil clean up based on thes~ criteria were determined to be 100 ppm of total volatile organics. the most conservative STEL. and 25 ppm. the most conservative TWA-PEL. Based on the regulatory requirement for facility closure. the appropriate level of clean up would be background. Clean up criteria were not established for the removal of the tank contents. Closure of the tanks will be done in strict accordance with 40 CFR 264.197. with appropriate decontaminatidn of the tank interiors. In accordanci with Section 300.68 of the National Contingency Plan. several remedial methods were developed in the feasibility stu~ to accomplish the objectives estap1ished for the penmanent remedy at the site. Two methods were developed to dispose of the contents of the storage tanks. two methods to address the onsite structures. seven methods to address the onsite contaminated soi1. and one method to address trash and debris on the site. A no-action alternative was also evaluated. Initial Screening of Alternatives Section 300.68 (h) states that the following broad criteria should be used in the initial screening of alternatives (methods): ------- TABLE 11 PERMISSIBLE EXPOSURE LIMITS FOR VOLATILE COMPOUNDS FOUND AT TRIANGLE CHEMICAL COMPANY OSHAl AOGIH2 AOGIH3 TWA (PPM) TWA (PPM) STEL (PPM) SOILS Acetone 1.000 750 1.000 Carbon Disulfide 10 Chlorobenzene 75 75 Dichlorobenzene 50-75 75 110 1.2-Dichloroethylene 200 200 250 Dioxane 100 25 100 Ethyl Benzene 100 100 125 Furan Tetrahydrofuran 200 200 250 TANKS Benzene 1 10 25 Dichlorobenzene 50-75 75 110 Dichloroethane 100 200 250 Ethyl benzene 100 100 125 Napthalene 10 10 15 1.1.2.2-Tetrachloroethane 5 1 5 Toluene 200 100 150 1.1.2-Trichloroethane 10 10 20 Trichloroethylene 100 50 200 OSHA TWA - Occupational Safety & Health Administration (OSHA) time weighted average. 2 AOGIH TWA - American Conference of-Governmental and Industrial Hygenists (AOGIH) time weighted average. :I AOGIH STEL - AOGIH short term exposure limit. ------- 9 (1) Cost. For each alternative. the cost of installing or implementing the remedial action must be considered. including operation and maintenance costs. An alternative that far exceeds (e.g. by an order of magnitude) the costs of other alternatives evaluated and that does not provide substanti~lly greater public health or environmental benefit should usually be excluded from further consideration. (2) Effects of the alternative. The effects of each alternative should be evaluated in two ways: (1) whether the alternative itself or its implementation has any adverse environmental effects; and (ii) for source control remedial actions. whether the alternative is likely to achieve adequate control of source material. or for offsite remedial actions. whether the alternative is likely to effectively mitigate and minimize the threat of harm to public health. welfare. or the environment. If an alternative has significant adverse effects. it should be excluded from . further consideration. Only those alternatives that effectively contrib~te to protection of public health. welfare. or the environment should be considered further. '. . (3) Acceftable Engineering Practices. Alternatives must be feasible for the locat on and cond1t1ons Of the release. applicable to the problem. and represent a reliable means of addressing the problem. Each of the remedial methods was evaluated based on these criteria. The rationale for preference of remedial methods is outlined below. v Methods for Disposal of Tank Contents 1. Offsite incineration/deep well injection/solidification and offsite landfill This method involves incineration of 32.100 gallons of ignitable liquids. deep well injection of 24.000 gallons of non-ignitable organic liquids. and solidification and offiste landfill disposal of 375 cubic yards of organic sludges. The method provides for destruction of more than half of the hazardous materials in the tanks. and minimizes the potential for direct contact with the sludges and materials that cannot be incinerated. There are several commercial incineration and injection facilities in the area. thereby'reducing the risks associated with transporting hazardous materials. For these reasons. the method is retained. - 2. Solidification and Offsite Landfil1ing of all Tank Contents This method involves the use of inorganic solids to absorb the liquids and transform the waste into a dry soid material. which is transported to an offsite landfill for disposal. The method is significantly more costly than the incineration/deep well injection method without providing a ------- 10 Method for Disposal of Drums and Contents 1. Offsite incineration and deep well injection of contents/offsite landffll of empty drums This i.s the only method developed for the disposal of 135 drums that are currently stored on the northern portion of Triangle Chemical Company's property. The contents can be bulked with similar liquids from the storage tanks and disposed of very cost-effectively. Methods for Disposal of Contaminated Soils 1. Excavation of contaminated soil and disposal in an offsite landfill This method is retained in the initial screening. This method involves removal of the contaminated so 11 s, and the disposal of these so11 s in anr', approved landfill offsite. The site would then be backfilled and graded with clean soil. Human contact with the contaminated material and'the potential for future groundwater contamination would be eliminated, thereby meeting all of the objectives for remedial action. 2. Excavation of contaminated soil and disposal in an onsite RCRA landfill In this method, a RCRA approved hazardous materials landfill for disposal of contaminated soils would be constructed onsite. This method is rejected' for the following reasons: (1) location of a landfill in the lOa-year floodplain is not a recommended practice; (2) because the wastes would remain onsite, a continued threat of release of wastes will exist; (3) construction of a landfill will require demolition of the onsite structure~; (4) extensive long-term maintenance and monitoring will be required; and (5) the costs are significantly higher than offsite transport and disposal with no additional health or environmental benefits. 3. In-Situ mechanical aeration of 50ils Aeration of the. so11 s is a phy~ical decontamination method whereby the contaminated soils are exposed to the atmosphere and the volatile organic compounds are. released under controlled conditions. Contamination is reduced to background levels in a short period of time, and capacity to manage wastes from other contaminated sites is created by not utilizing space at an offsite landfill. Post-closure activities associated with this method include groundwater monitoring and site maintenance. Also, this method is the least costly of all of the methods developed for soil remediation and will meet all of the objectives developed for the site. For these reasons, the method is retained for further evaluation. ------- 11 4. In-Situ Forced Air Injection Aeration of Soils This method may be technically infeasible for use with the type of soil found at the Triangle Chemical site. The clay soils will hinder the movement of air. thereby requiring extensive amount of time and electrical energy for a~equate exposure of the subsurface soils and release of the volatile compounds to the atmosphere. Associated with these time and energy requirements are higher operating costs. making this method more costly than mechanical aeration while not providing a commensurate increase in protection. For these reasons. the method is eliminated from further consideration. 5. Encapsulation of Contaminated 50il Construction of a protective cap over the site would provide adequate protection of the public from direct contact with the contaminated soil. as long as the cap is properly maintained and no future site development< " takes place. However. enscapsulation would not accomplish the objectives of preventing groundwater contamination and mitigating future i~pacts due to surface development. and would be difficult to maintain due to the location of the site. , , By allowing contamination to remain in the soil. a significant potential for groundwater contamination will exist. and long-term groundwater monitoring will be required in order to detect an contaminant migration from the site. If contamination is detected. future remedial action addressing the groundwater may be required. Capping the site will not eliminate the potential for uncontrolled releases of volatile organic compounds during future site development activities. thereby posing a serious health threat to future construction workers at the site. Because the site is located in the IOO-year floodplain of Coon Bayou. deterioration of the cap will be significant and long-term maintenance costs will be extremely high. A cap is infeasible along the bayou shoreline. where tidal action will cause continual cap erosion and exposure of contaminated soil. . For the reasofts discussed above. encapsulation is rejected as a remedial method . - Disposal 0' Trash and Debris 1. ~ation and Disposal in an Offsite Landfill Trash and debris will be separated into contaminated and uncontaminated material. The contaminated material will be disposed of in a RCRA-approved hazardous materials landfill. Over 95' of the material is non-hazardous. and will be burfed in a sanitary landfill. All of the material will be ------- 12 / Methods for Addressing Contaminated Buildings and Structures 1. Decontamination Buildings will be steam cleaned and remain onsite. The rinsate will be collected and disposed of by deep well injection. The method is technically effective and will eliminate the risk of public exposure to contaminants. Also, it may be possible to salvage the prefabricated buildings after decontamination. The method is retained. 2. Demolition and Removal Demolition and removal of the onsite structures is rejected because capital costs are significantly higher than the cost of decontamination, without a commensurate increase in benefits. . , ..., " The comparative costs of each of these methods are listed in Table 12. The costs 'associated with excavation to 25 ppm and 100 ppm are listed for comparison of methods that would not attain full compliance of Federal regulations, but would provide adequate protection of public health based on established health criteria. For all 50il alternatives that are not designed to reduce contamination to background levels, a total present worth of $75,800 must be added for site management and long-term monitoring. For example, the total present worth of site encapsulation (infiltration controls) with mechanical aeration including capital costs and operation and maintenance is $227,800. Description of Remedial Action Plans . The alternative methods that were retained after the initial screening are combined into alternative remedial action plans for a permanent 'remedy at the site. Cost estimates and brief descriptions of the technical feasibility, implementability, and environmental effectiveness of each plan are listed in Table 13. Detailed descriptions of the methods included in each plan are given below. The methods involving the disposal of onsite debris and storage tank contents and the decontamination of onsite structures are common to all of the alternative p1ans, and therefore need not be evaluated with each plan. For comparative purposes, the estimated costs of these methods are included in the total remedtal plan estimates. Disposal of Tank Contents and Decontamination of Tanks Approximately 32,000 gallons of liquids and sludges in the onsite storage tanks are amenable to incineration based on laboratory analysis of flashpoint, organic content, and heat value. One commercial incinerator operates near, the Triangle Chemical site, thereby reducing risk and cost associated with transporting hazardous materials. ------- TABLE 12 SUMMARY OF REMEDIAL ACTION METHOD COST ESTIMATES MONITORING AND MAINTENANCE REMEDIAL METHOD TOTAL CAPITAL COST ANNUAL PRESENT WORTH* TOTAL PRESENT WORTH Tank Contents So 11 d i fy and Landfil 1 An Contents $151,000 $151,000 Deep We 11 I nj ec t and I nc 1 nera te 118,000 118,000 Liquids, Solidify and landfill Sludges ContaMinated Soils Excavaton to Background Quality 1,510,000 1,510,000 and, Onsite Disposal Excavati on to 25 ppll Vol atl1 e 781,000 781,000 Organics and Offs1 te 01 sposal Excavation to 100 ppM Volatile 572,000 572,000 Organics and Offs1 te 01 sposal Excavation to Background Quality 868,000 868,000 and Offsite Disposal Mechanical Aeration for Volatile 62 ,000 62,000 Organics Renloval Forced Air Injection for Volatile 173,000 173,000 Organics Removal '164,000 Infil trati on Control s wi th Exclvati on 164,000 and Offs1te Disposal Infiltration Controls with Mechanical 152,000 152,000 Aeration Trash and Debris ~: Segregation and Offsite Disposal 14 ,000 14,000 Buildings and Structures " ..' Demolition and Removal 614,000 6~ ,J . ",I ------- ..: ..1 -, '.J . .:' ~ TABLE 12 (CONT.) SUMMARY OF REMEDIAL ACTION METHOD COST ESTIMATES MONITORING AND MAINTENANCE REMEDIAL METHOD TOTAL CAP ITAL COST ANNUAL PRESENT WORTH* Drums and Contents Removal with Offsite Disposal Site Management 39,100** Infiltration Control Method All Other Methods 5,300 500 49,800 4,800 26,000 26,000 TOTAL PRESENT WORTH 39,100 75,800 30,800 * Present worth values based on a discount rate of 1~ over 30 years. ** Cost will vary according to most applicable disposal technology. . . ------- TABLE 13 SUMMARY OF ALTERNATIVE REMEDIAL ACTION PLANS FOR TRIANGLE CHEMICAL COMPANY TECHNICAL ENVIRONMENTAL IMPLEMEtl- CAPITAL MONITORING/MAINTENANCE COSTS TOTAL PRESENT PLAN FEASIBILITY EFFECTIVENESS TABILITY COSTS ANNUAL PRESENT WORTH WORTH 1. Disposal of Ut11izes con- I Removes all Requires $1,167,000 $500 $5,000 $1,172,500 Tank Contents ventional tech- wastes and con- 2 months. and Trash, nolog1es. taminated mater- Perfom Decontami nati on L imi ts of con- 1als from site. duri ng dry of Structures, tam1nation to Air Missions season. Excavation to background during excava- Background qua 11 ty tion and tank Qua 11 ty unproven. opening. 2. Disposal of Util f zes con- Removes all Requires 385,000 500 5,000 390,500 Tank Contents vent10nal wastes and 2-3 months. and Trash, technologies, reduces all Perfom Decontam1ncat1on exceptsof 1 contaminants dur1 ng dry of Structures, aeration to background season. Mechanical method. P110t 1 evel s. Air Aeratf on of study recOMmend- emissions So11 s to ed prior to full duri ng mechan- Background implementation.. 1cal aeration Qual1 ty Limits of con-. of so11 sand tam1 nation to tank opening. background quality unproven. 3. Disposal of Utili zes con- Some contaminat- Requt'res 2 871,000 . 500 5,000 876,500 Tank Contents ventfonal tech- ed so11 s left months. and Trash, nolog1es. Field onsite. Con- Perfom Decontamination detenn1nat1on tamination below during dry of Structures, of so11 con- short-tenn season Excavation to tam1nant zone exposure limits. . . ... 100 ppm likely to be Air emissions Volat11e 1l11prec1 see during excavation. Or9~..fcs . i ------- TABLl 13 (CONT.) PLAN TECHNICAL FEASIBILITY ENVIRONMENTAL EFFECTIVENESS IMPLEMEN- TABILITY CAPITAL COSTS MONITORING/MAINTENANCE COSTS TOTAL PRESENT ANNUAl PRESENT WORTH WORTH 377,000 500 5 ,000 382,000 4. Disposal of Tank Contents and Trash, Decontamination of Structures, Mechanical Aeration of Sol1 s to 100 ppm Volatile Organics 5. Disposal of Tank Contents and Trash, Decontamination of Structures, Excavation of Sol1 s to 25 ppm Volatile Organics 6. No Action , ! i :. ~) ""::: ., Requi res 2-3 months. Perfonn duri ng dry sea son. Utilizes con- Some contaminated ventional tech- soils left onsite. nologies, except Contamination soil aeration below exposure method. Pilot limits. Air study recommend- emissions during ed prior to full excavation. implementation. Field detennin- ati on of sol1 contaminant zone likely to be impreci see Same as 3 N/A Same as 3 except con- tami nati on is below time weighted average exposure limit. Does not accom- pli sh si te objectives, Inconsistent with land use projected for area. Poten- tial for human exposure and threat to heal th and safety, poten- tial for con- tinued con- taminant min..a+inn. Same as 3 NA 1,080,000 500 5,000 1,085,500 NA NA NA NA . . . ------- 13 Deep well injection is an ~ppropriate disposal alternative for 24,000 gallons of non-ignitable liquids currently onsite. There are several facilities in the Gulf Coast Region which inject non-flammable, low. solids waste into saline groundwaters 4,000 feet below the ground surface. This technology, although not destructive, will essentially eliminate potential human contact with the tank materials. The sludges in the tanks would be solidified with an inorganic solid and landfilled at a permitted offsite landfill facility. Tanks would then be decontaminated by recirculating detergent water and rinsing. Final rinsate samples would be analyzed to certify that a tank would be decontaminated. Larger tanks would also be mechanically scoured, if necessary. All of the rinsate would be disposed of by deep well injection. Trash and Debris Removal with Offsite Disposal .;i. ". Offsite disposal is the only remedial action which is applicable to the site. Ninety-five percent of the trash is considered non-haza~ous, and would be transported to a sanitary landfill in the area. That portion of the debris that is obviously stained would be considered hazardous, and will be disposed of in a RCRA approved hazardous materials landfill. Decontamination of Onsite Structures Decontamination would be accomplished by steam cleaning all floors, ceilings, walls, and internal structures. The rinsate would be collected and disposed of by deep well injection. Certification would be required to ensure that the buildings were decontaminated before any future use would be possible. Offsite Disposal of Drums and Drum Contents The material s which are currently stored on the Triangle Chemical Company property north of Redbird Chemical, will be analyzed and bulked with similar materials found in the onsite storage tanks. The materials will then be incinerated or deep well injected, as appropriate. The drums will be decontaminated, crushed, and d~sposed of in a RCRA approved landfill. Differences in the alternative remedial action plans are attributed to the remedial methods developed as a permanent remedy for soil contamination at the site. Only the descriptions for the soils portion of each plan are given below. The complete plans include the selected remedial methods for the tank contents, drum and debris removal, and decontamination of the onsite structures. ------- 14 Plan 1 - No Action In accordance with Section 300.68 (g) of the National Contingency Plan (NCP). a no action alternative should be evaluated. This plan involves leaving the site conditions as they currently exist. Section 300.68 (h) (2) states that an alternative having significant adverse environmental effects or that does not effectively mitigate and minimize the threat of harm to public health welfare and the environment should be excluded from further consideration. The no action alternative would allow the site to continually pose a threat of: (1) a release of volatile organic contaminants in the soil to the atmosphere during future site development or flooding. (2) leaching of volatile organics into the groundwater during periods of heavy rainfall due to an elevated water table. (3) a release of tank contents causing extensive soil and surface water contamination. and (4) exposure of the public during unauthorized entry to the site. The risks to public " health and the environment associated with the no action plan are unacceptable and the no action plan is rejected. . . Plan 2 - Excavation and Offsite Landfill Contaminated 50115 are limited to the areas ons1te where releases from drums and tanks had occurred during and immediately after operation of the facility. The soils to be removed lie in a narrow band extending from about 1 foot below ground surface to just above the perched ground water table found at about six feet. A front end loader and a backhoe are required to excavate the soils and load trucks for offsite transport. A four-foot dike would be built to provide protection from the 100-year flood during"the excavation period. Soils from the dike would be used as backfill after the contaminated soil is removed from the site. Excavated soils would be transported and. disposed of in a RCRA approved double-lined landfill. Various levels of clean up were used for cost estimates based on (1) permissible exposure limits for several of the compounds identified in the soil and (2) regulatory requirements for facility closures. Volatilization of contaminants is expected to occur during excavation and transport. Thus soil being placed in a landfill may not be contaminated at the time of disposal. Because volatilization will be much mo~e difficult to control during excavation than during aeration. excavation .~ result in an undesirable environmental effect at the.site. The pros and cons of this alternative are listed below: Pros: + Equipment required is readily available in the area. + Utilizes conventional technology. + Removes contaminants from the site. + Only two months required for implementation. + Eliminates potential of future groundwater contamination. + Eliminates potential for release of volatiles during ------- 15 Cons: - Volatilization of contaminants will occur during excavation and transport. - Very high cost due to requirement for double-lined landfill facil1 ty. -Double-lined facility may not be readily available. Plan 3 - In-Situ Mechanical Aeration Contaminated soils will be exposed to the atmosphere under controlled conditions using a tractor with a disc harrow. Treatment consists of four- pass tilling of a six-inch soil layer. Treated layers will be excavated and stor~d in a diked area for use later as backfill. Soil sampling will be used to verify decontamination prior to excavation. Reduction of '.. contaminant concentrations to background 1 evel s wi" take approximately~.' hours depending upon the ambient air temperature at the time of r~edial action. Flood control structures wi". be built around the till- area to control run-on, and provisions will be made to manage possible runoff from the 1-hour 25-year rainfall event. The material from the dike, native clays, will be used as final cover and grade material for the site. A groundwater monitoring program will be established to ensure that the groundwater will be adequately protected by the remedy. The existing monitoring wells will be su,plementaed with one new shallow well at the north property boundary, downgradient of contaminated soil Area B. Air monitoring will be used to control the aeration operation. The areal extent of tilling can be varied to ensure that no offs1te air quality degradation occurs. Pros: + Least costly alternative to implement. + Volatilization can be monitored and remedy can be fmplemented under strfctly controlled conditions. + Does not depend Ufon the availability of an approved double-lined facf ity. . + Capacity at an offsite facility not consumed. + Potential for volatilization durfng future sfte development would be eliminated. + Risk due to transport of hazardous materials is el iminated. - + Action can be completed within one month Cons: - Innovatfve tec.hnology; would require a pilot study. - Background levels not set. ------- 16 1" the initial screening, the' construction of an onsite RCRA approved landfill for the disposal of contaminated soils and trash was rejected. The cost of this construction was estimated to be $1,510,000. The expense involves the special construction requirements for floodplain protection' and demolition of all onsite sturctures to provide enough area to build a landfill. Excavation of the soil to background levels and disposal at an approved offsite facility is estimated to cost $684,000. The costs of incineration and deep well injection of the tank contents must be added to each of these, and the cost of debr1s disposal and structure decontamination must be added to the offsite disposal alternative. The total cost of the onsite landfill alternative plan would be $1.63 million versus $1.17 million for the offsite disposal alternative. Excavation of the soil to background levels and offsite disposal, in combination with the recommended actions for the structures, tank and dr~ contents, and onsite debris also complies with the applicable environmerita1 laws and regulations. However, this is much more costly than the r~ommended alternative ($1.17 million versus $393,000> and does not offer a commensurate increase in benefits to human health and the environment. Also, because volatilization of the organic contaminants will occur during excavation and transport, it is likely that the soils will be effectively decontaminated prior to landfill disposal, and that landfill capacity could be better used for hazardous materials from other sites. Therefore, excavation and offsite disposal is not as cost-effective as mechanical aeration. Excavation of soil to 100 ppm and 25 ppm would provide adequate protection of human health and the environment based on permissible exposure limits to contaminants found in the soil, but would not fully comply with applicable laws and regulations. The difference in cost between excavation to 100 ppm' and excavation to background concentration is $296,000 ($1.17 million versus $876,000>, and between excavation to 25 ppm and background levels is $86,500. However, groundwater monitoring would be required for a 30 year post-closure period, and future corrective actions may be required if contaminant migration via groundwater was detected. It would therefore appear that excavation to background would be more cost-effective than excavation to either 100 ppm or 25 ppm, when the potential for future groundwater action$ at the site is considered. Community Relations Very little public interest has been expressed. The public notice period: began on April 5, 1985 and ended on April 19, at which time the public comment period began. A public meeting was held in Orange, Texas on May 1. Five people attended the public meeting, and no statements were made. The public comment period ended on May 10, 1985; one comment was received during the peroid. The comment and a written response are included in the ------- 17 Consistency with Other Environmental Laws It is EPA policy to give primary consideration to remedial actions that attain or exceed applicable and relevant standards of other Federal public health and environmental laws. The environmental laws which will have an impact on the proposed remedies for the Triangle Chemical site include: 1. The Resource Conservation and Recovery Act substantive requirements, 40 CFR Part 264, for closure of tanks and container storage facilities. 2. Executive Order 11988, Floodplain Management for sites located in flood plains. 3. Clean Water Act, water quality crietria for human health and drinking water. 4. Occupational Health and Safety Administration time weighted average-penmissible exposure limits for air quality monitoring. .... ... Closure of tanks and containers is regulated by the Resource Conservation and Recovery Act (RCRA) subparts I and J. Subpart I is the applicable regulation governing the closure of facilities in which hazardous materials were stored in containers. The subpart indicates that containers and soil containing or contaminated by hazardous wastes must be decontaminated or removed. The regulations in subpart J apply to facilities that use tanks to store hazardous wastes and state that, at closure, all hazardous wastes and residues must be removed from the tanks. RCRA also requires that offsite landfills used for disposal of hazardous wastes be double-lined, RCRA approved facilities. These requirements would also govern the construction of an onsite landfill. A brief description of all the applicable and relevant RCRA regulation is given in Table 14. Executive Order 11988 applies to the protection of floodplains. The Triangle Chemical site is located in the 100-year floodplain. Therefore any onsite remedy should be designed with.consideration given to floodplain protection. The Clean Water Act outlines water quality criteria for human health. These numerical standards are applied to address the issue of -how clean is clean" for the shallow groundwater at the site. The Occupational Safety and Health Administration time weighted average- permissible exposure limit standards are applied to ensure that no degradation of offsite air quality will occur during remedial action. .- . ..-. +'-,';-.-r" ------- TABLE 14 RCRA REGULATIONS APPLICABLE TO TRIANGLE CHEMICAL COMPANY 40 CFR DESCRI PTION (F APPLICABILITY TO IMPACT ON CONTAMINANTS REGULATION REGULATION TRIANGLE CHEMICAL REMAINING ONSITE 264.18 Facilities located in Parts of the. site are No present f1 ood protection. 100-year flood plain inundated by 5 feet of Tanks may need reinforcement, must be designed. water in a 100-year and contaminated areas may constructed. operated flood. Ti dal surges may need to be diked. and maintained to cause addi tional structural prevent washout of any damage hazardous waste ~y a 100-year flood. 264.50 A contingency plan to Liquids to be stored A contingency plan would be minimize hazards during onsite are hazardous required. an unpl anned release and ignitable. must be developed by owners of a hazardous waste facn i ty. 264.90 Facilities that treat. Liquids to be stored Legal interpretations may store, or dispose of onsite are hazardous. require groundwater monitoring hazardous waste must Hazardous wastes may if hazardous wastes are left establish groundwater remain in the soil. onsi tee protection standards which may include long- term monitoring for 30 years. 264 .178 Soils containing hazardous Hazardous wastes have Allowing wastes to remain onsite wastes and waste residues been found in onsite l- may be a violation of RCRA. must be removed or 5011 5. decontaminated. ..' .J ------- TABLE 14 (CONT.) 40 CFR DESCRIPTION OF APPLICABILITY TO IMPACT ON CONTAMINANTS REGULATION REGULATION TRIANGLE CHEMICAL REMAINING ONSITE . 264.191 Owners which treat or Liquids to be stored Existing tanks are of unknown store hazardous wastes onsite are hazardous. structural integrity and may in tanks must confom need to be modified. to tank design standards which define structural integrity. . 264.192 Tanks used to store Some liquids to be Tanks have no known liners corrosive hazardous stored onsite are or corrosion inhibition liquids must be equipped corrosive. systems and must be with an inner liner or modified. other corrosi on inhibition system. 264.192 Storage of hazardous Liquids to be stored Weekly tank inspections liquids in tanks re- onsite are hazardous significantly increase site quires an inspection management costs. schedule to assess tank conditions which incl udes at least ~ekly spot checks for signs of leakage. ,. .. ------- TABLE 14 (CONT.) 40 CFR DESCRIPTION OF APPLICABILITY TO IMPACT ON CONTAMINANTS REGULATION REGULATION TRIANGLE CHEMICAL REMAINING ONSITE , 264.197 Ignitable liquids must Some liquids to be Compliance with management be separated and managed stored onsite are regulations may require with respect to extreme i gni table. costly monitoring instru- heat or pressure, mentation. uncontrolled toxic mists, and uncontrolled flammable fumes. 265.198 Ignitable liquids must Some liquids to be Compliance may require be stored in tanks stored on-site are costly construction of which comply with ignitable. tank storage area dikes requirements of the and proper drainage National Fire Protection systems. Association. Penmit applicants Guidance Manual for hazardous waste land treatment storage, and di sposal facilities. Agency considers contamination to be removed when the concentrations of hazardous constituents in the soil are at background levels. Sets criteria for. soil cl eanup Required for full compliance with Federal Environmental Regulations and Guidance. . .- ------- 18 Recommended Alternative Section 300.68 (j) of the National Contingency Plan states that "The appropriate extent of remedy shall be determined by the lead agency's selection of the remedial alternatives which the agency determines is cost- effective (i.e. the lowest cost alternative that is technologically feasible and reliable and which effectively mitigates and minimizes damage to and provides adequate protection of public health, welfare or the environment)." To this end, incineration and deep well injection of the tank and drum contents, decontamination of all onsite structures, offsite disposal of trash and debris, and mechanical aeration of the contaminated soils is the recommended remedial action for the Triangle Chemical site. Schematic drawings of the mechanical aeration method of this alternative are presented in Figures 7 and 8. This alternative complies with the closure requirene~ts for tanks (40 CFR 264 subpart J) and container storage facilities (40 CFR 264 subpart I). This alternative is also the lowest cost alternative that will comply with all applicable and relevant Federal environmental laws and regulations. Decontamination of the soil to background levels would effectively mitigate the potential for future groundwater contamination. Operation and Maintenance Post closure monitoring and maintenance will be required for any remedial plan selected for the Triangle Chemical site, although post-closure activities will be more extensive for alternatives in which wastes remain onsite. For all plans, post closure activities will include vegetation control, fence repair, and quarterly groundwater monitoring from existing monitoring wells to verify that the groundwater is not impacted by remedial construction. . For plans that do not clean up contaminated soi15 to background levels, additional groundwater monitoring and site surface maintenance will be necessary for a period of up to 30 years. Operation and maintenance for the recommended alternative will involve landscaping and fence repair at the site, groundwater monitoring from the three existing onsite monitoring wells, and construction of an additional shallow monitoring well at the site boundary directly downgradient of soil contamination. Area B. Groundwater monitoring will be performed for a period of 5 years. If no significant contamination is detected in the monitoring wells by the end of this period, the remedy will be considered effective and further monftorfng will not be requfred. If significant contamination is detected during the monitoring period, corrective .easures will be evaluated. Annual operation and maintenance costs for the recommended alternative is estimated to be $500 and the present worth is estimated to be $5000. Schedule Approve Remedial Action Award Cooperative Agreement for Design Award Cooperative Agreement for Construction June, 1985 June, 1985 June, 1985 ------- ~....-_..~ tru , 11 -.- - HOII[I OfflC( ..... It8M88 .. . 'T ~ t- ...-.-.- - .. ,.. U8'IIIIII .. co.818UC11011 DnAIL :~ 1 . i .. OJ :. .,. . "., .-cJII ~'III) . -- FIIOPEATY ----------- ,'! '. ." . ',.:.: '''.. . e, 0' .'.. '. ;'. .1'; ~~ j;..'. .~~-j. <:Lo:~:.~'! . .:i "'."".: LOACMi ooar ,.... LCWIING' --DING PROCESS ...... NO , -- .... CHOIDL NOPoT'l 0000 0000 LOADING OOCK . PROCfSS IULbHG NOI PIIOCfSS --DING N02 .8t8IAtID DEPTH or COIIf-..aTED IOIL8 AMA At'." AllEA . t'''' . ...& C t'''' " , , " TRwG.f Cl4EI8CAL iMC1f1€Rn UN[ .. , ~3 ~ tU .... C 8AYOU ...n I. Fi oure 7 nlA.... elllMIeAL eOMPAilY 1. ------- 5ECTION A-A TYPICAL .~ ACCESS GRADE 'it ~ 2' VERTICAL EXTENT OF CONTAMINATION 0.5' TRANSITION TO CLEAN ZONE ~~ . LJ' TYPICAL DETAIL FOR CUT STABILITY 2 ~~ SECTION .. . 0 ' Hazardous V Information! US EPA Regie Philadelphia, " UNCONT~~I~ATED COVER' '. .,.oE ILOPE OICTAftD. oa, ~.. -.-.0 ~A11ON .... 6' VERTICAL EXTENT OF CONT AMINATED lOllS . TYPICAL .~ ACCESS GRADE I--- "0' 0." TRANSITION TO CLEAN ZONE 1/ " . ~ 'I " UNCONTAMINATED COVER TYPICAL'" ACCESS ORAD VERTICAL EXTENT , " 6' OF CONTAMINATED SOILS 0.5' TRANSITION TO CLEAN ZONE TYPICAL .~ ACCESS ORADE LEGEND ~ NOTE: VERTICAL ICALE EXAGGERATED TO SHOW CONSTRUCTION DETAIL ~ UNCONTAMINATED COVER Figure 8 TRIANGLE CHEMICAL COMPANY I [8, TLL ,ZON! ~. 'Jt .YEGETATION SOIL TILLING SECTION VIEWS, t .. ...-... ------- |