How a Bad Phase I ESA Can Cost Your Development Millions

A Phase I Environmental Site Assessment (ESA) is often the first due diligence step in a property transaction. Phase I ESAs are a quick, simple, and relatively inexpensive way to gauge potential environmental liabilities. However, if conducted poorly, a Phase I ESA can lead to big assumptions, big problems and big money wasted further down the road.

Whether intentional or not—a lot of weight is typically placed on the findings of a Phase I ESA. What businesses operated on site? Where should we sample? What would our cleanup costs be? The initial Phase I ESA is often the first source of information a project is built upon. Big decisions—and often big money—are based on the words of this initial low-cost investment. This is great if a thorough Phase I ESA has been conducted. However, if conducted poorly, it’s like buying a house without checking the foundation—you could be burning cash in the long run.

So how do you make sure the “foundation” is being checked? How do we avoid getting a bad Phase I? The simple answer is to get it done right the first time. FLS recommends hiring experienced environmental firms for any environmental Due Diligence efforts, including Phase I ESAs. If the price of a Phase I ESA sounds too good to be true—it probably is. Environmental due diligence is the last thing you want to cut corners on. Cutting corners leads to mistakes—and mistakes are where money is lost.

How are Mistakes Made in Phase I ESAs?
The truth is the findings of a Phase I ESA are often very subtle. Determining environmental liabilities from mountains of data is similar to finding a needle in a haystack. A single marked tank on a Sanborn Fire Insurance Map can be easy to miss to the untrained eye. Combine this with the fact that Phase I review work is often conducted by less experienced and entry-level staff—important findings can sometimes be missed. The consequences of not finding a leaking tank can be the difference between a $10,000 investigation/cleanup and spending 10 times that amount in investigation/remediation/schedule when an unanticipated tank and contamination are found during excavation.

In fact, our staff at FLS are regularly retained by clients to review and confirm the findings of other firms’ Phase I ESAs. Mistakes and missed items are not at all uncommon. Sometimes they are subtle findings that do not affect a client’s acquisition or any projected site remediation. However—other times these missed items could result in a multimillion-dollar cleanup.

The last thing a developer needs is to walk onto a construction site they thought was clean—only to find grossly polluted soil 10 feet into the excavation. It is wasted time and wasted money. All due to false or inaccurate assumptions derived from a poorly conducted Phase I ESA. Although, it’s tempting to bargain shop for cheap Phase I ESAs, saving a few thousand dollars on this task could potentially cost millions and derail the development. That’s why FLS recommends spending a bit more resources upfront and hiring an experienced environmental firm to prepare your Phase I ESA. This ensures it is conducted correctly—and you won’t run into any “Million Dollar Surprises” on your Site. For all of your environmental due diligence needs, contact Mark Hutson at 212-675-3225 or mark@flemingleeshuecom.

Environmental Forensics – How can it help you?

Common questions about contamination very often arise on many sites: Is this “my” contamination? Did it originate from somewhere else? When did it happen? How much am I responsible for?Environmental forensics can assist your project in myriad ways. It is not always about pointing a finger at someone else—although sometimes it is—it is about finding the real source of the issue on your own site. Think of it as a diagnostic tool. Identifying one source from a number of possible site sources.

Forensics means more than just a chemical fingerprint. It means using all available information to understand a source: chemistry, history, land use, contaminant distribution. Sometimes it means using very simple analyses to crack the problem. For instance, at an example Site, water infiltration in a basement caused a concern that the vapor/waterproofing barrier breached and incoming contaminated groundwater would harm residents. Others had tried to identify the source using conventional chemical analyses but had been unable to determine the source. FLS tried a different approach and collected basic groundwater quality parameters to assess the situation. By plotting these data effectively, the information was transformed into an understandable and diagnostic tool. FLS arranged and plotted the data as shown below.

Careful forensic analysis combined with the site operational knowledge led to the conclusion that groundwater from a breached barrier was not the source; rather, the source was from an internal equipment malfunction that flooded the basement! The radically different conduit fingerprint was the key to identifying the source of the basement water. This meant the difference between a routine mechanical fix and a prolonged and costly investigation and interaction with the regulatory agency. With FLS’s finding, the regulatory agency was immediately removed from the equation—and the plumber called.

At FLS we understand these issues and routinely use environmental forensics to answer questions about contaminant sources and site issues. Through consultation and analysis, we can help you resolve questions of contaminant source, date of release, and other practical questions for site management. Our clients often come to us because they know we will think “out of the box” and develop solutions to their unique problems, usually environmental, but not always. Let us know how we can help you! Please see our website at to find more about our company and the services we offer. You can also call 212-675-3225 or email Mark Hutson at

Censored Data – What is it and what does it mean for my project?

What are censored data and what are the implications for your project?  These are two very good questions and the second can have a significant bearing on your management decisions, remedial actions, and approach to regulatory agencies.

Censored data are analytical results reported below a detection limit, e.g., < 2 ug/L, ug/m3, etc.  They appear in most environmental datasets because there are often many non-detect values.  This means the result is too low for the instrument or analytical method to yield a reliable number.  It also means that the result is unlikely to be zero and that there is possibly some amount of contaminant in the sampled medium.

Historically, the way of handling non-detects was to substitute one-half the detection limit or some other arbitrary value, or in some cases eliminate non-detects from the analysis altogether.  Ignoring non-detects means you are tossing out useful information.  Substituted, i.e., fabricated, values create an invasive signal that potentially distorts the meaning of the measured data (Helsel 2012).[1]  If you insert artificial values, you are declaring that you know something that you do not.  Fabricated values can deform your dataset and give unreliable and/or incorrect results (Helsel (2012). These invasive data can lead to poor or incorrect decisions about remediation or whether a cleanup goal has been reached, or even if remediation is required.  Ignoring censored results can leave the odds stacked against you because you are omitting low end values, which can bias the remaining results high.  Why report your results higher than they really are? This can have large, adverse, and unnecessary cost implications.  If you ignore censored data, then this is what you may be doing whether you realize it or not.  Likewise, if you are not handling censored data properly, you are possibly saying something that is not true, or at least inaccurate.

Being able to use and understand censored data can be very advantageous when handled properly.  Here is an example. The question was whether Trichloroethene (TCE) was higher in sub-slab soil vapor in one location versus a second location on the same property.  Approximately 40 percent of the sampling results were below detection limits. Visual examination of the numerical results could not discern a difference.  A graph of the results—always plot the data regardless—showed a difference, but it was not known if the difference was significant.  Only the proper statistical analysis could do that, but this was complicated because so much of the data were censored.  FLS analyzed the data statistically employing methods that accounted for the censored data without the loss of information.  The result was that there was no statistical difference in the soil vapor concentrations from the two location, despite the apparent difference observed by visually examining the graphs.

At FLS we understand how to deal with censored data and can use the information in it to your benefit.  Sometimes, there can many non-detect values in your data. Why not put this information to good use instead of throwing it away, or leading you astray? FLS can help you with that. And help you get the most out of the costly information you obtained. Being able to use this information can have huge cost implications.  But without it, you never know what could have been, or what was but was not really necessary.

[1] Helsel, D. R. Statistics for Censored Environmental Data Using Minitab and R, Second Edition. Published 2012 by John Wiley & Sons, Inc., p.2.

NYSDOH Update to Vapor Intrusion

The New York State Department of Health (NYSDOH) recently updated its guidance criteria for evaluating the potential threat for vapor intrusion caused by contaminated media. Keep reading to see how these changes can affect your property…

NYSDOH’s 2006 Guidance for Evaluating Soil Vapor Intrusion in the State of New York (2006 Guidance) provides recommendations for soil vapor intrusion based on matrices that compare sub-slab to indoor air contaminant concentration levels. The recent update includes significant changes to these matrices such as the addition of a new compound (methylene chloride), a new matrix for vinyl chloride, and more stringent criteria for certain compounds.

NYSDOH defines soil vapor intrusion as the process by which volatile chemicals migrate from a subsurface source into the indoor air of building. Soil vapor is found in the pore spaces between soil particles and can migrate into buildings through openings in the foundation (i.e., cracks in basement slabs or sidewalls, utility penetrations, etc.). The migration of these volatile chemicals into living spaces can be a direct threat to human health.

Actions recommended in the NYSDOH matrices are based on the relationship between sub-slab vapor concentrations and corresponding indoor air concentrations. These actions include:

  • “No Further Action”
  • “Take reasonable and practical actions to identify source(s) and reduce exposures” (source likely due to indoor/outdoor air, not soil vapor); determine the source of chemical contamination and taking reasonable and practical action to reduce exposure.
  • “Monitor” to evaluate whether indoor air or sub-slab vapor concentrations have changed. Monitoring may also be appropriate to determine whether existing building conditions (e.g., positive pressure HVAC systems) are maintaining the desired mitigation.
  • “Mitigate” to minimize current or potential exposure; common mitigation methods include sealing preferential pathways, installing a sub-slab depressurization system (SSDS), or adjusting the pressurization of a building in addition to monitoring the indoor air and sub-slab vapor concentrations. NYSDOH may consider this as an interim measure prior to remediation or an engineering control as part of post-remediation Site Management.

These changes may affect your property if it will be developed or is in post-remediation Site Management under regulatory programs such as the New York State Department of Environmental Conservation (NYSDEC) or New York City Mayor’s Office of Environmental Remediation (NYCOER). Even if you have a property that is not currently under NYSDEC or NYCOER oversight, the recent changes may create potential liability issues and/or complicate future real estate transactions (i.e. refinancing, property sale, etc.).

Some ways FLS can help you…

  • Determine how the changes affect your property and provide recommendations based on your priorities.
  • Perform an evaluation of existing vapor mitigation measures (such as a SSDS) and current soil conditions to identify if there are ways to reduce the system and/or if there is an opportunity to remove the system entirely, particularly if bulk contamination was removed and current concentrations no longer pose a threat to human health and the environment.
  • Prepare a cost analysis to show how removing or reducing vapor mitigation measures affects your operational costs.

FLS has been successful in reducing Site Management responsibilities for many clients and reducing their financial burden by evaluating current conditions and working with regulators to evaluate the threat of vapor intrusion. At numerous sites, we are working with our clients and the regulatory agencies to switch from active to passive SSDS and in some cases remove the SSDS requirement entirely by showing that either the site is no longer a threat or that engineering controls block the pathway for intrusion.

For additional information on how these updates impact your property and how FLS can help you manage your environmental costs and liability please contact Mark Hutson at our New York City office at 212-675-3225 or