Phase 1 Environmental Site Assessment

What To Expect & Everything You Need To Know To Make Sure You're Prepared So You Can Achieve Site Closure!

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Phase 1 ESAs protect site owners from liability

What Is A Phase 1 Environmental Site Assessment?

A Phase I Environmental Site Assessment - and all ESAs that may follow - are designed to identify any RECs that may be present on a property. RECs or "recognized environmental conditions" are any environmental contaminant, hazard, or liability that threatens the health and safety of anyone on or near the contaminated site.

The process of a Phase 1 ESA is to carry out a detailed investigation or characterization to determine whether or not there is likely to be any type of contaminant or liability present on the site that needs to be addressed before either the sale or construction of or on a site is allowed to progress. Much of the work associated with Phase 1 can be conducted off-site. Still, certain aspects of the investigation must be completed on-site such as searching for aboveground storage tanks (AST) or underground storage tanks (UST).

Once this phase of an ESA has been completed, what happens next depends on the information discovered during Phase 1. No further action is required so long as no liabilities, hazards, or contaminants are present.

However, if it is determined the site is contaminated, a Phase II ESA is required. During Phase 2, they will take extensive samples of groundwater and soil to determine various characteristics of the state of contamination. The information discovered will then aid them in determining the appropriate steps required to clean up any present contaminants.

Phase 1 ESAs Are To Investigate Potential Contaminants

Why Is A Phase 1 ESA Important?

There are many reasons why ESAs are essential. The information they can divulge about a site's potential hazards and liabilities can save a lot of hassle down the road. They can ensure that no hazards, contaminants, or liabilities threaten the health and safety of plants, animals, and humans in or around the site.

Site investigations also allow us to ensure that there are no hazards in drinking water that people on site or nearby will be exposed to. In some cases, contaminates can cause serious health concerns and even death, so ensuring there are no contaminates threatening to harm the lives of those in or around the site is very important from an environmental sustainability standpoint.

A Phase 1 Environmental Site Assessment aims to determine if a threat in the soil, groundwater, or both needs to be addressed. Specific guidelines for groundwater - such as the Drinking Water Regulations put out by the EPA - and soil help determine what levels are safe for various environmental contaminants.

Specific contaminants can even stop the growth of plants and harm the lives of the local ecosystems. These investigations are significant for the sake of the environment, the lives and well-being of those nearby, and even the property's value.

What is covered in a Phase 1 ESA

What Does A Phase I Environmental Site Assessment Cover

There are many things covered in a Phase I ESA. The environmental consultants will pull records and files from the databases of various federal, state, local, and even tribal agencies, companies, and groups to determine the risk associated with the property. These records and files will tell the consultants many things, such as:

  • Location of any aboveground storage tanks
  • Location of any underground storage tanks
  • History of chemical spills
  • History of chemical leaks
  • historical use cases of the property
  • detailed list of the past owners
  • any chemicals purchased, used, stored or created on the property
  • the existence of any currently or formerly used injection wells

The above list is by no means comprehensive, but it does list some of the main things investigated during this phase of the site investigation, but these are some of the main things that will be considered when determining whether or not a Phase 2 ESA will be required.

How much time does a Phase I ESA take

How Long Do Phase I ESAs Take To Complete?

A Phase 1 ESA can take anywhere from 2 - 6 weeks, depending on the amount of information available. Generally, the more information available for a site, the more time it will take, as more loose ends need to be investigated by the remediation team.

On the contrary, the less information available usually means a shorter amount of time is required during this investigation phase, but this is only sometimes the case. In some cases - especially with older or defunct sites - records may be hard to find, incomplete, or poorly documented. In some instances where this is the case, it can take more time. However, as long as the consultants can confirm the presence of any environmental contaminants, it is safe to move to Phase 2 of the investigation.

Cost Of A Phase 1 ESA

Phase 1 Environmental Site Assessments usually cost between $2000 - 5000$ usually, but various factors can influence this cost. Phase 1 of the investigation, however, is the most affordable.

Phases 2 and 3 are much more expensive, as both phases can each cost anywhere from $5000 to $150,000+. The main reason the second and third phases of a site assessment can be so expensive is the level of scientific investigation and specialization required in Phases 2 and 3.

What Is The Goal Of A Phase 1 ESA

The ultimate goal of a Phase 1 ESA is to determine whether or not contamination exists on the property. Using various sources of information and any information gained during on-site inspections, your remediation team will assess the likelihood of contamination.

If it has been confirmed that there is some environmental hazard, contamination, or liability present - to protect those in or around the site, as well as the site owner - a Phase 2 ESA will be required to determine the best course of action needed to successfully deal with whatever was found.

Three Phases Of ESAs

What Are The Different Phases Of Environmental Site Assessment

Many types of ESAs can be used for various situations, but the main three you'll hear about are Phase 1, 2, and 3 ESAs.

You already understand what the purpose of Phase 1 is, so we'll not go into detail regarding that, but below we will briefly explain what Phase 2 and 3 are for, what they hope to accomplish, and when they may or may not be needed.

Phase 2 ESAs

Once a Phase 1 ESA has been successfully carried out, and it has been determined contamination does exist, it is then mandatory to move into the second phase of a site investigation.

During a Phase 2 ESA, extensive sampling will be done - generally in stages - allowing environmental consultants to determine many crucial things. Some things that can be discovered are the type of contaminant(s) present, the horizontal and vertical distribution of any contaminants, and what remedial applications and remedial reagents may be the most effective in disposing of said contaminant(s).

Phase 3 ESAs

Once the type and dimensions of any present contaminations have been confirmed and the environmental consultants have developed an appropriate remedial strategy, it's on to Phase 3.

A Phase 3 ESA is the remediation phase when the contaminant, hazard, or liability is dealt with through various remedial applications. It can be dealt with through in-situ (in-place) remediation or ex-situ (out-of-place) remediation.

Below we'll go into the main aspects involved with phase three - remediation & analysis. Whether an environmental consultant decides to use ex-situ or in-situ remediation, once the remedial application has been completed, there is a lot of analysis to ensure the conditions are acceptable to achieve a site closure.

Ex-Situ Remediation

With ex-situ remediation, heavy machinery physically removes all contaminated materials. The contaminated materials will either be disposed of or treated in a different location on-site or in a specialized facility. Ex-situ is usually a more expensive option. In most cases, it requires excavating the contaminated material, handling and transferring it, treating it in a specialized facility, or disposing it in specific places designated for this exact purpose.

The primary issue with ex-situ remediation is that some contaminated material can be left behind - depending on how it's done. If this happens, regardless of what was done to the materials that were removed - whether they were treated or replaced - the contamination that remained will not have any way to be treated and can continue to infect the soil and groundwater.

In-Situ Remediation

However, in-situ remediation is usually more affordable, and depending on which remediation technology you use, it can also be much more effective.

There are generally two types of in-situ remediation. They are known as in-situ chemical oxidation and in-situ chemical reduction. With in-situ oxidation, you're introducing chemical oxidants into the contaminated materials to destroy any present environmental contaminants and pollutants.

With the in-situ reduction, chemical reductants are introduced to break down, degrade and reduce the presence of any toxic organic compounds. The power of these methods, chemical oxidation and reduction can be intensified if combined to destroy the contamination. When they are put together, they both strengthen and feed one another in what is known as a "redox" reaction. If your consultant decides to opt for in-situ remediation, the best bet would be to find a remediation technology that takes advantage of this "redox" reaction.

The way these reactions for chemical reduction and oxidation are introduced is generally with the use of various drilling services. Typical means for introducing these remedial reagents are sonic drilling, rotary drilling, direct push drilling, and a few others.

However, there are other ways these can be applied. Depending on the vertical distribution of the contaminant, one of the most reliable ways to introduce reagents is by using excavation equipment to mix contaminated soil with the reagent. Mixing soil in this manner ensures the remedial specialists can be sure all contaminated materials have had adequate contact with the reagents and will have the best chances of being successfully treated.

Careful Analysis

Once remediation has been completed, consultants are tasked with ensuring the contaminants have either been destroyed or are reduced to such an extent that they are no longer an issue. Various samples will be taken to document the success of any remediation efforts.


In conclusion, a Phase 1 Environmental Site Assessment is meant to determine the likelihood of any source of contamination, hazard, or liability on the site. ESAs protect the public, the site owner, and the ecosystem.

Certain situations may trigger the need for a Phase 1 ESA, such as requirements from an external agency, switching the primary usage of the property, selling the property, etc.

If it is verified that contaminants, hazards, or liabilities exist on site, a Phase 2 ESA will be required. Once more information has been collected, that will, in turn, trigger a Phase 3 ESA. These phases work together to destroy or remove any source of contamination. These phases help protect property owners from unforeseen health and safety hazards.

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Environmental Remediation Specialists

Remember, while DeepEarth Technologies, Inc. passionately shares knowledge and educates on various topics, we do not offer site assessment services. Our services are specialized in site remediation.

If you've got a site contaminated with hydrocarbons or chlorinated solvents, you can either give us a call, request a quote, or contact us with any questions to be connected to an environmental specialist.

DeepEarth Technologies, Inc. has been cleaning up contaminated sites for more than two decades. For any environmental remediation needs, feel free to request a quote, give us a call, or contact us to speak to a specialist.

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