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DuPont Pompton Lakes Frequently Asked Questions
as of 5 November 2008

1. Why should a vapor mitigation system be installed in my home?

If your home is located within the proposed area for installation of vapor mitigation systems, you are in an area where shallow ground water contamination is known to be at levels above the NJDEP Ground Water Screening Levels for the vapor intrusion pathway. Elevated soil gas vapors have also been identified beneath many homes within the contaminated ground water area (plume area). This means that there is the potential for soil gas vapors from the contaminated water to migrate upwards into the indoor air of your home at some time.

Installation of mitigation systems would prevent a future indoor air concern from occurring or fix an existing indoor air concern, if one exists. Please note that even if migration of soil gas vapors into the indoor air is not occurring now, vapors still could migrate into your home at any time in the future, undetected by the occupants.

2. If I do not allow DuPont to install a vapor mitigation system, what will happen?

Consistent with the NJDEP Vapor Intrusion Guidance document, DuPont will be required, at a minimum, to collect 1 sub-slab soil gas sample from each home that does not allow the installation of the vapor mitigation system. Depending on those results, additional sampling may or may not be required. DuPont is not required to conduct any additional rounds of sampling if no contaminants are detected in the first round.

3. Should I decide whether to have a mitigation system installed based on indoor air sampling results only?

No. In this case, indoor air sampling is being conducted only to identify the general indoor air quality of your property at a particular moment in time. It does not represent the potential for soil gas vapor to migrate into your home. For this reason, indoor air sampling is not to be used as a decision-making tool for deciding whether to have a vapor mitigation system installed.

In order to know whether a potential vapor problem exists from contaminated ground water, indoor air sampling is typically coupled with sub-slab soil gas sampling. NJDEP has already confirmed the presence of elevated soil gas vapors in your neighborhood and DuPont has agreed to install vapor mitigation systems in each home. Therefore, additional sub-slab sampling for each home is not required by NJDEP.

4. If I want DuPont to sample my indoor air a second time, will they?

For those properties within the potential vapor mitigation investigation area, DuPont will conduct additional indoor air sampling at your property if you have agreed to accept the installation of a vapor intrusion mitigation system and DuPont is unable to arrange for installation of the system before the end of the winter months. Otherwise, DuPont is not required to conduct additional indoor air sampling.

5. What criteria are the indoor air and sub-slab soil gas sampling results being compared to?

Site-specific Indoor Air Comparison Levels and Sub-Slab Soil Gas Comparison Levels were developed using a new low-level method of analysis at the DuPont Pompton Lakes Works site. Comparison levels for the 10 contaminants of concern are available below.

Chemical Site-Specific Indoor Air
Comparison Levels (ug/m3)
Carbon tetrachloride 1
1,1-Dichloroethane 510
1,2-Dichloroethane 0.8
1,1-Dichloroethene 220
1,2-Dichloroethene (cis) 36
1,2-Dichloroethene (trans) 73
Tetrachloroethene (PCE) 1
1,1,1-Trichloroethane 1,000
Trichloroethene (TCE) 1
Vinyl chloride 0.5


Chemical Site-Specific Sub-Slab Soil Gas
Comparison Levels (ug/m3)
Carbon tetrachloride 13
1,1-Dichloroethane 5,000
1,2-Dichloroethane 8
1,1-Dichloroethene 2,000
1,2-Dichloroethene (cis) 350
1,2-Dichloroethene (trans) 700
Tetrachloroethene (PCE) 16
1,1,1-Trichloroethane 22,000
Trichloroethene (TCE) 11
Vinyl chloride 5

6. What happens if my levels exceed the Indoor Air Comparison Levels for a contaminant of concern?

If indoor air levels exceed the Indoor Air Comparison Levels DuPont will evaluate the home conditions for the need for interim actions and confirm the schedule for installation of remedial sytems.

7. Who should I contact if I have additional questions?

  • Mindy Mumford of the NJDEP Site Remediation Program should be contacted at (609) 777-1976.
  • David Epps of DuPont can be contacted at (973) 492-7703.
  • NJDOH Hazardous Site Health Evaluation Program can be contacted at (609) 584-5367.


DuPont - Pompton Lakes Works
Pompton Lakes, Passaic County
PI# 007411

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