Nature of Dioxin Contamination - Regulatory History and Authorities. Dow Chemical Midland Facility. March 15, 2010

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1 Nature of Dioxin Contamination - Regulatory History and Authorities Dow Chemical Midland Facility March 15, 2010 Al Taylor DNRE

2 Dow Overview 1,900 acre facility in Midland, Michigan. Operated from 1890 present (Over 100 years). Manufactured vast array of chemicals: Plastics Military chemicals Pharmaceuticals Organic chemicals Inorganic chemicals Brine-derived elements Herbicides & pesticides Not just a dioxin issue Later CAG discussions on other contaminants of concern

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4 Dioxins What is dioxin? Group of chemicals Expressed in ppt TEQ ppt = parts per trillion TEQ = toxic equivalence Where is it found? Statewide (1-35 ppt) 6 ppt TEQ state average Primary contaminant of concern at Dow plant and AOC Site Michigan soil direct contact criteria 90 ppt TEQ 4

5 What is a Dioxin Result? Dioxins chlorinated dibenzo-p-dioxins 2,3,7,8-TCDD 1,2,3,7,8-PeCDD 1,2,3,4,7,8-HxCDD 1,2,3,6,7,8-HxCDD 1,2,3,7,8,9-HxCDD 1,2,3,4,6,7,8-HpCDD OCDD TEF Dioxin Furans chlorinated dibenzofurans 2,3,7,8-TCDF 1,2,3,7,8-PeCDF 2,3,4,7,8-PeCDF 1,2,3,4,7,8-HxCDF 1,2,3,6,7,8-HxCDF 1,2,3,7,8,9-HxCDF 2,3,4,6,7,8-HxCDF 1,2,3,4,6,7,8-HpCDF 1,2,3,4,7,8,9-HpCDF OCDF TEF Dioxin TEQ (ppt) DLT-PCBs non-ortho substituted PCBs 77, 81, 126, 169 mono-ortho substituted PCBs 105, 114, 118, 123, 156, 157, 167, 189 TEF

6 RCRA Permit U.S. EPA Corrective Action EPA began conducting dioxin studies in the Midland area in the early 1980s. Permit was issued in 1988 (HSWA). Contained Corrective Action Requirements. 6

7 Corrective Action Under U.S. EPA 1980s - Focus on Source Control Focused on 2,3,7,8 TCDD Identified dioxin contamination in the City of Midland, but values were below levels of concern at that time Wastewater treatment plant and incineration complex identified as sources Corrective action focused on source control: Closure of On-Site Waste Units (WMUs) RGIS Upgrade Wastewater treatment plant operations modified to significantly reduce discharge of dioxin. Incineration complex operations modified to significantly reduce emission of dioxin. 7

8 Where are we in the process and how did we get here? EPA also recommended several precautionary measures to Midland residents: Eat less Tittabawassee River fish Limit contact with contaminated soil EPA recommended additional Off-site work as part of HSWA Permit 8

9 Where are we in the process and how did we get here? (Cont d.) MDEQ authorized by EPA to administer the corrective action program in Michigan MDEQ Soil Dioxin Sampling - Midland Dow Soil Dioxin Sampling Midland and Plant MDEQ Investigation of Tittabawassee River State issued Dow operating license MDEQ Investigation of Saginaw and Shiawassee Rivers and Saginaw Bay 9

10 What is Corrective Action? Phased process to address historic, current, and future releases from active hazardous waste management facilities Companies are subject to corrective action for releases that occur within and beyond the plant site boundary regardless of when release occurred 10

11 DOW HAZARDOUS WASTE FACILITY OPERATING LICENSE 6/12/03 HAZARDOUS WASTE MANAGEMENT OPERATIONS OFF-SITE CORRECTIVE ACTION ON-SITE CORRECTIVE ACTION MIDLAND AREA SOILS TITTABAWASSEE RIVER AND FLOOD PLAIN SAGINAW RIVER AND FLOOD PLAIN AND SAGINAW BAY 11

12 Dow Midland Operations

13 Corrective Action On Site Waste Management Units Facility SWMU* - The area within the Facility boundary; includes WMUs listed below LEL Sites I, II, and III (Dioxin Point Sources)* Poseyville Landfill* No. 6 Brine Pond (6-Pond) and Brine Injection Wells Within the Facility Boundary* Chemical Disposal Wells No. 1, 2, 3, 4, 5, 8 and Landfill* Closed Diversion Basin and Open Wastewater Conduits Sludge Dewatering Facility * Indicates WMUs that were in the 1988 Federal permit 13

14 Corrective Action On Site, Cont d. Six Areas of Concern East-Side Powerhouse Cooling Pond Ash Pond Triangle Pond US-10 Styrene Tank Farm Pure Oil Site Overlook Park 14

15 LELs I, II and III 15

16 Dow Midland Operations 16

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19 Dow Chemical Midland Facility - Current 19

20 Perimeter Groundwater Control Structures 20

21 Corrective Action Interim Response Activities Interim Response Activities (IRAs), to address immediate concerns and prevent the spread of contamination: IRAs conducted at Dow include: Outfall 001/Sand Bar Area Upgrades/expansion of East-Side RGIS (1994 present) RGIS installed around T-Pond Barrier controls for surficial dioxin contamination T-Pond solids removal project Reach B and Reach D removal/capping projects Anticipated to be part of final remedial action for the facility 21

22 RGIS Upgrade Construction 22

23 Corrective Action Where is Dow in the corrective action process? Varies In some cases, investigation is just beginning (e.g., Pure Oil AOC) For some WMUs, significant corrective action has been completed and Dow is in a monitoring and maintenance mode (e.g., RGIS, Sludge Dewatering Facility) In other cases, investigation and remediation will be guided by the Compliance Schedule (e.g., T-Pond Till Sand Investigation) 20 + item Compliance Schedule has been prioritized based on potential for off-site releases and human/environmental exposures 23

24 Incineration ballasted clarification tertiary effluent sand filters Revetment Groundwater Intercept System Tertiary Ponds WWTP with activated sludge treatment Trickling filter to treat phenolic waste Delivered to storage ponds Direct discharge to the Tittabawassee River Clean Water Act (CWA) Clean Air Act CWA, Amendments of 1972 Brine Processing with graphite electrodes (furans) RCRA Safe Drinking Water Act Land Ban Provisions of HSWA Clean Air Act, Amendments of ,4,5-T Production (approximately ) 24

25 Corrective Action Off Site Investigation Activities Why conduct additional work in 1996? Historic studies focused on only one dioxin congener: 2,3,7,8-TCDD Now necessary to look at the 17 dioxin and furan congeners with dioxin-like toxicity 1988 Federal hazardous waste permit required additional investigation Michigan residential direct contact criterion is 90 parts per trillion (ppt) TEQ vs. the 1,000 ppt 2,3,7,8- TCDD value used by EPA in 1980s 25

26 What is a Dioxin Result? Dioxins chlorinated dibenzo-p-dioxins 2,3,7,8-TCDD 1,2,3,7,8-PeCDD 1,2,3,4,7,8-HxCDD 1,2,3,6,7,8-HxCDD 1,2,3,7,8,9-HxCDD 1,2,3,4,6,7,8-HpCDD OCDD TEF Dioxin Furans chlorinated dibenzofurans 2,3,7,8-TCDF 1,2,3,7,8-PeCDF 2,3,4,7,8-PeCDF 1,2,3,4,7,8-HxCDF 1,2,3,6,7,8-HxCDF 1,2,3,7,8,9-HxCDF 2,3,4,6,7,8-HxCDF 1,2,3,4,6,7,8-HpCDF 1,2,3,4,7,8,9-HpCDF OCDF TEF Dioxin TEQ (ppt) DLT-PCBs non-ortho substituted PCBs 77, 81, 126, 169 mono-ortho substituted PCBs 105, 114, 118, 123, 156, 157, 167, 189 TEF

27 Dioxin Investigation Activities Off Site In 2001, DEQ received a grant to conduct a baseline investigation of Tittabawassee River sediments and flood plain soils Results reported in 2002 Elevated concentrations in study area Results consistent with Environmental Response Division s Phase 1 and Phase 2 dioxin investigations of floodplain soils Results used to make case for Offsite Investigation of Tittabawassee and Saginaw Rivers included these areas in Dow s 2003 Hazardous Waste License 27

28 Dioxin Investigation Activities Off Site Summary (not intended to be a complete list!) 1983, 1984 and 1986 EPA and Dow investigations of Midland and Tittabawassee River 1996: DEQ sampled Midland Community : DEQ developed state-wide background 1998: Dow conducted follow-up study to 1996 DEQ investigation : DEQ conducted Tittabawassee River sediment and floodplain soil studies 2003: License Issued with Off-site Corrective Action Requirements 2004: Wild Game Study 2004: GLNPO Study Saginaw River and Bay and Non- Tittabawassee Tributaries 2006: Dow Implements Midland Bioavailability Sampling Plan : GeoMorph Investigation of Tittabawassee River and Floodplain UM DES and MSU Studies (not agency required) 28

29 Presentation Summary 1,900 acre facility that has operated over 100 years and produced a vast array of chemicals and wastes Extensive contamination both on and off-site, extending over 50 miles from Midland into Saginaw Bay Complicated technical and regulatory history Corrective action is taking place under a State RCRA permit issued in 2003 and CERCLA AOC issued in January of 2010 Progress is being made

30 Thank you! Questions? 30