Skip directly to search Skip directly to A to Z list Skip directly to site content








X = TCE Level in well.

(µg/L or ppb)

5 > X
5 < X < 50
50 < X < 130
130 < X < 260
260 < X < 2000
2000 < X
2 yr
8 mo
4 mo

yr = year, mo = month, wk = week, immed = immediately, and TCE = trichloroethylene.

The above table presents a suggested time frame to implement protective measures in order to protect public health from both chronic toxicity and an excess lifetime cancer risk (1 x 10-6) due to multiple pathways (i.e., drinking, bathing, and showering). Note that the above table assumes no previous exposure or other routes of exposure. The time-frame for implementing actions to protect public health and/or to monitor tap water would also be dependent upon the length of previous exposure, current exposure, the status of the groundwater contamination plume, or continued use of the groundwater resources for drinking, cooking, bathing, or showering.


Dublin TCE Site Work Plan Developed by EPA in 1987 Consent Agreement
and Order - Page 1

Exhibit I

In accordance with criteria established by EPA, point-of-use water treatment systems will be installed and periodic water sampling will be performed on selected private wells. The EPA established four categories, or tiers, to guide appropriate action for each well. Each tier addresses a TCE concentration range and appropriate corrective action and follow-up monitoring. The following outline describes each of the tiers. Tables 1 through 4 list the wells and observed TCE concentrations in Tiers 1 through IV respectively.

Tier I

    - TCE concentration range: Greater than nondetected but less than 5 micrograms per liter (µg/L).
    - Corrective Action: None required.
    - Monitoring: Well water will be sampled twice annually.

Tier II

    - TCE concentration range: 5 to 75 µg/L.
    - Corrective Action: At the discretion of the well user, either bottled water will be supplied or a granular activated carbon (GAC) treatment system will be installed at the tap used for cooking and drinking (kitchen tap).
    - Monitoring: Treated tap water will be sampled quarterly, and untreated well water will be sampled twice annually.

Tier III

    - TCE concentration range: 76 to 260 µg/L.
    - Corrective Action: A GAC treatment system designed to treat the entire water system will be installed at all residential dwellings. At businesses, bottled water will be supplied, or a GAC treatment system will be installed at the tap used for drinking water.
    - Monitoring: Treated tap water and untreated well water will be sampled quarterly. In the event treatment systems are in place, samples will be conducted before and after treatment.

Tier IV

    - TCE concentrations range: Over 260 µg/L.
    - Corrective Action: Same as Tier III.
    - Monitoring: Treated tap water and untreated well water be sampled quarterly. In the event treatment systems are in place, samples will be conducted before and after treatment.

The work plan includes a phased approach for the completion or implementation of all tasks outlined by the four tier system, as described below.


Phase I

BCM will perform the following tasks prior to initiation of Phase II:

    - Determine the accessibility of each residence or business listed in Tables 1 through 4.
    - Obtain bids from contractors who can provide and install appropriate treatment systems within a specified time table.
    - Determine the preference of each residence or business for bottled water or kitchen tap treatment.
    - Prepare a specific sampling schedule for treatment systems and wells.
    - Retain a contractor who will provide bottled water on a demand basis.

Phase II

Phase II will include the provision of supplied water and installation of GAC treatment systems.

The following tasks are included in Phase II:

    - Implement a bottled water delivery program for those residences in Table 2 (Tier II) and businesses in Tables 2, 3, and 4 who choose bottled water over kitchen tap treatment or drinking water supply treatment systems.
    - Install a kitchen tap water treatment system at those residences in Table 2 (Tier II) and a drinking water supply treatment system in businesses in Tables 2, 3, and 4 who choose treatment over bottled water.
    - Install a full water treatment system at those residences listed in Tables 3 and 4.
    - Install a flow meter on all residences and businesses with treatment systems.

Phase III

Phase III will consist of the monitoring program, maintenance of treatment systems, and provision of bottled water.

The following tasks are included in Phase III:

    - Conduct periodic sampling of treated water from those systems with GAC treatment and of untreated well water in accordance with the schedules described above for each tier.
    - The first full set of samples (all wells before and after treatment) will be analyzed for volatile organic compounds (VOCs) by gas chromatography (GC), using EPA Method 601. Thereafter, samples will be analyzed for TCE, PCE, and vinyl chloride by Method 601, unless other VOCs are detected in the first set of samples, in which case, such VOCs will also be analyzed.
    - Conduct a full round of sampling at the completion of Phase II.
    - Record flow rates concurrent with sampling each residence or business with a treatment system.
    - Periodic maintenance of GAC treatment systems will be performed in a manner consistent with the system provided. This will normally consist of replacing the carbon bed.
    - Maintain the provision of bottled water, as appropriate.
    - BCM Quality Assurance/Quality Control (QA/QC) procedures will be followed in collecting and analyzing all samples. QA/QC for monthly sampling will be covered during quarterly sampling.

The effectiveness of treatment systems will be evaluated after each sampling event. System repairs of maintenance will be performed whenever TCE concentrations are found greater than 5 µg/L in drinking water. The work plan shall remain in effect for at least 1 year after the effective date of the Consent Agreement. After 1 year, the sampling program will be evaluated, the sampling frequency and treatment system maintenance schedules may be adjusted and a new, modified work plan, approved by EPA, may be placed into effect.

Treatment and sampling will continue until it has been demonstrated to the satisfaction of EPA that TCE levels are consistently less than 5 µg/L. Such determinations will be made for each well on a case-by-case basis.


The implementation of the work plan will be triggered by the signing of the Consent Order.

Task Completion Time (Days)
Phase I
Phase II
Phase III

* Dependent on access to the individual properties

1991 Modifications

The following section was not available in electronic format for conversion to HTML at the time of preparation of this document. To obtain a hard copy of the document, please contact:

Agency for Toxic Substances and Disease Registry
Division of Health Assessment and Consultation
Attn: Chief, Program Evaluation, Records, and Information Services
Branch, E-56
1600 Clifton Road NE, Atlanta, Georgia 30333



Figure 1. Site Map

Figure 2. TCE Concentration Contour Map



This document was released to the public for review and comment. Although the public comment period ended April 5, 1991, some comments were received after that time. Those comments and a response to the comments follow.

COMMENT: Water at the Whistlewood Apartments had TCE concentrations as high as 2,000 ppb, not a maximum of 500 ppb as reported.

RESPONSE: PADOH contacted the EPA Remedial Project Manager for the site to determine if data were available to indicate that the well water at Whistlewood Apartments contained higher levels of TCE than previously reported. No data are available to indicate that levels of TCE in water at the Whistlewood Apartments were greater than reported.

COMMENT: Whistlewood Apartments has 244 units, not 144 as reported.

RESPONSE: The Whistlewood Apartment manager states that the complex contains 144 units, not 244.

COMMENT: The installed charcoal treatment units for Tier I and Tier II did not treat TCE-contaminated water for all uses, as reported. These units treated kitchen tap only.

RESPONSE: That is correct. The 1987 Consent Agreement stated that the owners of water supplies that contained 5 to 75 µg/L TCE could choose to be supplied bottled water or have a treatment system installed at the kitchen tap. Those water supplies with less than 5 µg/L TCE were to be monitored twice a year, and the owners were not supplied bottled water or a treatment system. After consultation with ATSDR, EPA amended the consent agreement in 1991 to provide full-house treatment systems for all water supplies that contain TCE above 5 µg/L.

COMMENT: At a 1986 conference between the On-Scene Coordinator and ATSDR, it was agreed that biological monitoring of the exposed population would be conducted, but this was never implemented.

RESPONSE: ATSDR agreed to inquire about the capability and usefulness of biologically monitoring the exposed people. At that time, the Centers for Disease Control and Prevention (CDC) had no methods to test TCE levels in exposed people. Therefore, the study could not be conducted. Currently, a test is available to measure VOCs, such as TCE, in blood serum. However, that test is only for recent exposures. Some other tests are now available that may indicate if damage has been done to certain organ systems, such as the liver and renal systems, because of past exposure. Tests such as those may be useful to the community.

COMMENT: The [1986] Thompson-EPA Consent Decree did not provide an adequate level of treatment to the Tier II homes, which had levels of TCE up to 75 ppb and only received tap filters. This went on for over four years.

RESPONSE: The 1987 Consent Agreement was modified on April 25, 1991, by EPA, in consultation with ATSDR, to provide for full-house water treatment. Until that time, either tap filters or bottled water were provided.

COMMENT: The Roy F. Weston hydrogeologist opined in 1986 that, when the Whistlewood Apartments opened in 1974, the water delivered to the 244 families contained over 500 ppb of TCE. Individual homeowners and businesses surrounding 120 Mill Street were dosed with levels at or exceeding this at an even earlier date. These exposures continued until 1986.

RESPONSE: The contamination was not discovered until 1986. No data are available to substantiate or dispute the hydrogeologist's opinion.

COMMENT: ATSDR ignored one or more tests of installed, on-site monitoring wells, as opposed to the two pre-existing plant wells. The levels of TCE in the monitoring well directly downgradient from the rear of 120 Mill Street plant was in excess of 15,000 ppb.

RESPONSE: PADOH contacted EPA and inquired about this information. EPA does not have any data to reflect that information. You are welcome to provide any laboratory data that you have for our evaluation. Please include any quality control/quality assurance information with the laboratory data.

COMMENT: Dublin Borough officially requested ATSDR to include the residents of the Borough in its national TCE Registry, but was turned down.

RESPONSE: The TCE subregistry is closed at this time to new registrants. However, the information on the health of people that are included on the registry will, hopefully, provide important information in the future that can be used by all people exposed to known levels of TCE. Some publications on the information obtained to date are available through ATSDR's Division of Health Studies. Additionally, if data indicate a need to expand the registry or if new members are needed, Dublin residents will be considered for inclusion.

COMMENT: Tier II families bathed, showered and did their laundry in TCE-contaminated water (up to 75 ppb) for over four years after EPA and ATSDR knew of their predicament.

RESPONSE: All of the actions, including descriptions of the two ATSDR health consultations, taken at the site are described in this public health assessment. Any specific questions about EPA's decisions should be addressed to EPA.

COMMENT: The statement...that "[A]ffected parties in Dublin are currently being supplied treated water by the municipality to correct the problem" is incorrect. The municipality does not have the funds to take any actions to remediate the release of hazardous substances from 120 Mill Street. Although the Borough has not done so, it will install public water to the affected homes, if provided funds from the PRPs or EPA.

RESPONSE: The correction has been made in this document.

COMMENT: ..., ATSDR states that: "[S]pecifically, if data or information indicate that exposure to TCE through the domestic use of groundwater is currently occurring, then this site will be evaluated." TCE exposure through use of domestic water wells is occurring. See [previous] comment.

RESPONSE: Some clarifications have been made in this document to better reflect what information is needed for further evaluation.

COMMENT: The Borough reiterates its call to ATSDR to undertake medical and biological monitoring of the residents, along with an epidemiological study of those persons exposed to TCE.

RESPONSE: Your request will be given to ATSDR's Division of Health Studies for consideration. The Division will determine if a health study would benefit the community. If ATSDR determines that the community would benefit from a health study, one will be considered as resources become available.

Table of Contents The U.S. Government's Official Web PortalDepartment of Health and Human Services
Agency for Toxic Substances and Disease Registry, 4770 Buford Hwy NE, Atlanta, GA 30341
Contact CDC: 800-232-4636 / TTY: 888-232-6348

A-Z Index

  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #