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What is Remediation after a Phase 2 Environmental Site Assessment?   Recently updated !

What is Remediation after a Phase 2 Environmental Site Assessment?

Remediation refers to the process of cleaning up a property with contamination issues that are usually discovered during the Phase 1 Environmental Site Assessment (ESA) and Phase 2 Subsurface Investigation process. Today, there are a variety of remediation methods and technologies to apply at a site. And environmental professionals can optimize the process for maximum effect and lowest cost. For instance, the type of chemical, or the extent of the contamination plays a major role in selecting the optimal remediation technique. Moreover, the type of media (for example- soil, soil gas and/or groundwater) is another important factor in the remedial action methodology. Lastly, the available timeframe and budget, as well as the extent of regulatory oversight for the contamination cleanup process, also plays a part in the formation of a remedial action plan. Updated February 18, 2020.

Altogether, one must understand that each site is unique, and it is necessary to consult a professional geologist or environmental engineer to determine the appropriate course of action. 

Prior Investigations

A Phase 1 Environmental Site Assessment looks for Recognized Environmental Conditions, which are “red flags” that warrant subsurface contamination testing. The secondary process of this assessment refers to a Phase 2 Environmental Test, or Phase II ESA, and typically includes soil, soil gas, and groundwater sampling. The samples undergo laboratory analysis for common contaminants, indicating the presence of contamination, or lack thereof. And if contaminants are observable above Phase II ESA Screening Levels, one can reasonably presume requirements for remediation and mitigation actions. However, a Phase II ESA will rarely comprise enough data to begin the cleanup process.

Additional Investigations

In essence, all Phase 2 Environmental Site Assessments are “limited” investigations because they are made affordable. Thus, Phase II ESA reports are typically shallow subsurface tests and don’t fully delineate the lateral and vertical extent of a contamination plume. Usually, if contamination above screening levels are observable, one or more Additional Subsurface Investigations will become the next phase requirement. This effort aims to produce data for the clean-up process and comprises deeper samples than the initial Phase II ESA. It is in order to create an accurate representation of the contamination plume. Judging by the final results of this site contamination model, engineers and geologists then prepare the best course of action with regards to cleanup, also known as a Remedial Action Plan.

Remediation Action Plan (RAP)

After enough information is gatherable by the Additional Subsurface Investigation process, professional geologists then decide how to go about cleaning up the site. The goal of remediation is to restore the subsurface as close to the natural state as possible, and also to reduce human and wildlife exposure to harmful contaminants. There are many ways to remediate a site with subsurface contamination. But the processes often group into a few general categories. For instance, if the remediation technology applies directly to the subsurface, without removing any soil or groundwater, it is “in-situ” or in-place treatment. On the other hand, if the soil is excavated, or groundwater pumped, in order to bring the media to treatment, it is called “ex-situ.” Alternatively, natural attenuation is the process by which a subsurface contamination plume dilutes and degrades on its own over time, and is verified by monitoring and periodic confirmation sampling.

Mitigation vs Remediation

Sometimes environmental engineers can reduce human exposure and health risks by implementing walls, barriers or caps to isolate the contamination plume before it migrates to an end-point. This process isn’t remedial, but rather mitigative. And typically, vapor intrusion mitigation measures occur alongside remedial action methods, to ensure the safety of onsite occupants.

Remediation action plan descision

In-Situ Remediation Options

In-situ remediation methods do not require excavations, nor any pumping of groundwater. For some sites, these methods can be part of an effective, yet energy- and waste- efficient cleanup plan. In-situ treatment always applies directly to the subsurface. And the process usually involves adding, or injecting an agent to accelerate the breaking-down of contaminants. Additionally, these methods can be minimally disruptive to ongoing business operations on-site (depending on logistics).

Chemical Oxidation

In-situ chemical oxidation (ISCO) typically relies on an oxidant to react with and break down contaminants. To illustrate, a common oxidant such as hydrogen peroxide can be strategically injected underground at specific depths and volumes, with the intent to react to contaminants. The result is a chemical and physical change into daughter products which are understandably less harmful, or completely harmless. In the process, technicians introduce the oxidants into the subsurface using existing wells, or new injection points via direct-push drilling. And the oxidant can even be combined with a catalyst, such as iron to speed up the chemical reaction and make the process more efficient.

Chemical Reduction

In-situ chemical reduction (ISCR) is similar to ISCO except for the fact that it utilizes reducing agents (usually a metal such as iron) that can react with other toxic metals (most commonly chromium) to make them less harmful. In fact, ISCR commonly applies to clean up the solvent known as trichloroethene, or TCE. Typically, the process includes injecting the reducing agent directly into holes drilled into the groundwater table. However, another method comprises a technician creating a semi-permeable underground wall made of the reducing agent, to allow the groundwater to be treated as it flows through the barrier.

Thermal Treatment

In contrast to harnessing a chemical reaction for remediation, in-situ thermal treatment uses heat to remove a wide range of chemical contaminants. By injecting steam, applying steel pipe heaters, or using electricity to create heat underground, the chemicals of concern undergo evaporation and degradation. After thermal treatment, the resulting soil gas can controllably migrate to the surface, and undergo further treatment if necessary. Thermal treatment is one of the optimal methodologies to clean up sites with non-aqueous phase liquids (NAPL) contamination

Air Sparging

This technique is technically in-situ but is also a supplement to the soil vapor extraction process, which is an ex-situ process as well. After the injection wells are drilled deep enough to reach groundwater, an air compressor then pumps air into the groundwater table, within the well-casing. This agitating exposure accelerates the volatilization process of chemicals, so they may become vapor-phase, and extract via the SVE system. And after the vapors draw up through the extraction wells, the air undergoes treatment with carbon or thermal applications, prior to atmospheric release.

soil vapor extraction SVE remediation after phase ii esa


Bioremediation utilizes microbial activity to break down contaminants. Harmless bacteria, that occur naturally in the soil and groundwater, can consume and metabolize petroleum products, solvents, and even pesticides. However, the challenge of bioremediation is creating an environment where the select-bacteria can thrive. As a result, it may be necessary to add amendments to the soil, such as other bacteria, in order to make sure populations are large enough to consume the contaminants efficiently. Bioremediation is an attractive option because it uses natural microbial action, and it can take place in-situ. Alternatively, microbial action can occur ex-situ.

Ex-Situ Remediation Methods

When there is a large concentration of contamination that must commence quickly, responsible parties may consider ex-situ treatment. Ex-situ remediation methods typically involve a costlier and lengthier scope of work for cleanup. Whether impacts exist in soil, groundwater, or soil gas, the overall concepts comprise removing the contamination from its place underground and undergoing treatment above ground or off-site. For example, extraction and pumping from the subsurface. And depending on the extent of contamination and impact, a combination of these methodologies might be the most optimal approach to cleanup.

Soil Vapor Extraction

Soil vapor extraction (SVE) is an ex-situ treatment that does not involve the addition of any chemicals or reactive agents. Rather it utilizes extraction wells and vacuum pressure to draw out the vapors from chemicals as they volatilize (change into a gas) underground. The extraction wells are typically set within the vadose zone, which is a soil mass generally above groundwater, but below the ground surface. In fact, soil vapor extraction works best with dry soil. And when contamination exists in the saturated soils as well, deeper injection wells may apply to utilize air sparging methods, alongside SVE.

Soil Excavation

Contamination source excavation remediation is an original method of site clean-up. When there is a large concentration of chemicals in a relatively small amount of soil, it makes sense to excavate the site. Using traditional excavation equipment such as backhoes and dozers, contamination is removable from the site. And disposal methods include exportation to treatment facilities with appropriate certification. And in some cases, the soil contamination may undergo treatment on-site.

contamination remediation by excavating

Thermal Desorption

Another ex-situ way to treat soil is by applying heat. To illustrate, heat is applicable at strategic temperatures to volatilize or evaporate the chemicals out of the soil. Typical applications are by flame or by heating elements. Similarly, the in-situ thermal treatment uses subsurface heating elements to volatilize contaminants underground. In fact, large flame application chambers can heat and treat approximately 25 tons of contaminated soil per hour.

Pump and Treat

When groundwater is the target media of contamination, similar clean-up techniques can apply. Although, a strategic network of wells pumps the groundwater into a holding tank or an on-site treatment apparatus. Afterward, the clean groundwater returns through the system, which results in a pump-back into the same aquifer, or a nearby surface water system. In fact, under the proper permitting protocol, the resulting water may also end up within the local storm drain. A few ex-situ options to treat groundwater in this way include bioremediation, air stripping, and activated carbon treatment.

groundwater remediation pump and treat diagram

Activated Carbon

Carbon is a well known, highly efficient filter media that removes contaminants from air and water. For pump and treat applications, the water is run through an activated carbon filter. It’s here where common contaminants stick or “sorb.” The carbon removes all or most volatiles and hydrocarbons from air and water that passes through. And after treatment, the effluent air or water is environmentally friendly for discharge. Eventually, the carbon also needs retreatment by thermal desorption, in order to reuse. Alternatively, the carbon can just be sent to a proper landfill after serving its purpose.

Air Stripping

The air stripping method applies primarily to volatile organic compounds that are dissolved in water. These contaminants typically have a higher capacity for volatilizing by exposure to air and agitation. After the water is pumped into the aeration tank comprising the air stripper, it trickles down through a filter media that exposes the maximum surface area to the air. Simultaneously, a fan circulates air upwards from the bottom of the chamber, and the water passes through as it cascades. In essence, the contaminants volatilize and migrate to the top of the tank in vapor-phase. The resulting vapor can then undergo carbon treatment, per the descriptions above, before exhaustion into the environment.


In some cases, an acceptable course of action alongside remediation is to simply isolate the contaminants. In fact, by sealing off the source-area, one prevents contamination from further migration. This mostly applies to the protection of people and wildlife downgradient from a source-area. There are various containment methods involving vertical and horizontal barriers. For instance, a slurry wall. Although, the most common technique is capping.


This is a relatively straightforward procedure that involves putting a protective layer above or below a contamination plume. The most basic form of capping exists as a concrete or asphalt layer along the ground surface, with a vapor barrier. For example, these barriers can exist within a subterranean garage foundation overlying contaminated soil. Alternatively, a slurry or clay layer can apply atop and below a contamination plume in subsurface conditions. For example, landfills install these layers above and below the garbage they place underground. Vapor barriers are technically part of the mitigation effort, which can occur simultaneously to the remediation process. Furthermore, sites with higher contamination concerns might comprise multiple layers, comprising clays and other materials, along with a vegetative layering. Ultimately, the goal is to prevent toxic contaminants from migrating into other exposure pathways.

Ecological Revitalization

Ecological revitalization is an over-arching remediation plan that aims to return a contamination site to a more natural state, without the use of human engineering methods. By replanting native wildlife, enriching the soils, and providing wildlife habitat, land managers can provide aesthetic benefits and increase property value at the same time. And, ecological revitalization plays an even greater role, serving a very functional remedial purpose beneath the surface.

Evapotranspiration Covers

Plants can play an important role in remediation and are often the top layer to a capping strategy. In fact, with proper vegetation, the roots of plants draw water out of the ground and circulate it back into the air. The textbook term for this process is “evapotranspiration.” Additionally, it’s important for scientists to select the right soils for this strategy. And planners typically select a fine-grain combination of silt and clay that will be capable of holding high volumes of water. Moreover, it is important to prevent rainwater from percolating down to the level of the contaminants. This is because the chemicals can further-percolate downward, into the groundwater. As a result of proper soil and plant selection, absorbent sediments and thirsty roots can help to prevent the water from migrating.

Monitoring Natural Attenuation

Another common method of remediation is Monitoring Natural Attenuation (MNA). Natural attenuation refers to the environmental degradation of contaminants over time. And the keyword “monitoring” applies because of the importance to keep track of the degradation progress. And regulatory agencies typically prefer monitoring to proceed until safer levels of contamination are apparent. Usually, consultants and agencies prefer this method alone, for sites with low-level contamination or where time is not an issue. Otherwise, natural attenuation monitoring occurs alongside other remediation methods. Monitoring Natural Attenuation can also take decades to complete. Nonetheless, the same principles apply to qualify a site for clean-up closure.

Natural Attenuation Remediation


Resilience is the ability of the land to recover and is an important concept in land management. Natural attenuation speaks to the extraordinary capacity of the environment to return to a point of stasis over time. Today, scientists understand that the natural systems on earth do return to a state of balance. However, there is a limit to what ecosystems can handle. As a result, humans must assist with remediation efforts for the preservation of the natural earth. And in doing so, the environmental industry will continue to improve on remediation methods, as well as sustainability technologies, in order to afford a more natural environment.

Remediation Professionals

With so many options available to landowners today, navigating the remediation process can be a daunting task.  Fortunately, there is ample assistance readily available through your local environmental professionals.

It is important to remember that each site is unique, and it is necessary to consult with a licensed professional geologist or engineer in order to determine the appropriate course of remedial action.


Written By: Michael Joseph Sabo

Edited By: Adam Azad Kaligi, PG


US Environmental Protection Agency

American Petroleum Institute

United States Geological Service

Forward-Thinking Geologists, Engineers & Contractors!

What is the Phase I Environmental Site Assessment Process?

What is the Phase I Environmental Site Assessment Process?

The Phase I Environmental Site Assessment process comprises a rigorous review of a property’s history, along with a physical inspection of the current conditions. And the end result is a lengthy report that follows regulation standards. For the convenience of Clients, environmental consultants usually provide executive summaries at the front of each report. Nonetheless, the entire Phase I ESA process has to follow the guidelines and standards of the American Society for Testing and Materials (or ASTM). If environmental concerns become apparent during the Phase I Environmental Site Assessment process, additional tasks (such as a Phase 2 Subsurface Investigation) become a requirement. Updated November 18, 2019.

What is the Phase I Environmental Site Assessment Process

What is the Phase I Environmental Site Assessment Process

1. The Initial Request for a Phase I ESA

A Phase I ESA can be per the request of one party, or all the entities and parties within a transaction, altogether. And because it is part of the real estate due diligence process, a Phase I Environmental Site Assessment is typically for a good reason. Nonetheless, it clears up any hidden legal and environmental liabilities in association with a property.

The Environmental Questionnaire

At the start of the Phase I Environmental Site Assessment process, an Environmental Questionnaire helps evaluate the general risk of a property, for lenders, buyers, agencies and other information seekers. The questionnaire is a form for the ESA “report user” to complete. In fact, the results of a questionnaire may prompt a Phase 1 ESA, or dismiss it altogether.

2. Finding an Environmental Professional

Upon identifying the fact that a Phase 1 ESA report is a requirement, report users must find an environmental professional with the appropriate professional licensing. For instance, a professional geologist or environmental engineer with state certification, and who has five or more years of ESA experience. Undoubtedly, it is important to verify that the consultant qualifies as an “environmental professional,” per the ASTM standard.

3. Property History Researching

The initial order of business in the Phase I Environmental Site Assessment process is research. This task includes compiling all the available historical files and data on a property. For example, off the bat, a consultant will schedule a file review with the State Water Board, as well as the other oversight agencies. Similarly, the environmental professional may also order government database compilation reports from third-party information vendors. Such orders are typically for back-up and the verification of facts. In actuality, there could be hundreds of data parameters to research. Consequently, the data gathering process can take up to 15 business days to complete, if not more. Simultaneously, a comprehensive review and study of the data are performed, for the formation of final conclusions and recommendations. And the data gathering process must meet the minimum requirements of the ASTM standard to qualify.

Rushing a Phase I ESA

Rushing a Phase I Environmental Site Assessment is always possible. Although, it is not the best recommendation by consultants. For instance, a rush Phase I ESA may have a five to six business day turnaround time. However, the regulatory agencies can’t provide their files within such a short timeframe. As a result, the file review at the government agency becomes an omission within the assessment. And this omission constitutes a limitation in the overall ESA, impacting the conclusions. On the other hand, a proper timeframe for the assessment allows for most agencies, if not all, to respond in time. Thus, resulting in the proper ASTM-compliant Phase I Environmental Site Assessment process.

4. ESA Physical Site Inspection

In addition to robust historical research, the Phase I ESA process also requires a physical inspection of current conditions and activities on site. This task intends to cover all grounds for the evaluation of environmental liability. For instance, a property may have always been vacant, and accordingly documented as such. Thus, no apparent environmental condition happens to exists by record. However, there could also be ongoing illicit dumping and pollution at the lot. Often times, this is unknown to the current owner and oversight agency. And if such impacts affect the quality of the subsurface, the owner can face penalties and cleanup obligations. Apart from this, all users of Phase I ESA reports must understand that phase one site inspections are not equivalent to regulatory environmental compliance audits.

5. The Phase I Environmental Site Assessment Process

Upon approaching the final stages of the Phase I Environmental Site Assessment Process, a final report compiles all the information and data, along with conclusions, recommendations, and professional certification. Often times, Phase I ESA reports are in excess of 350 pages. Thus, consultants do provide executive summaries, which comprise a brief synopsis of the findings and conclusions. Executive summaries tend to be anywhere from two to three pages long.

6. The Phase 1 Reliance Letter

Phase I Environmental Site Assessment reports are deliverable only to the official authorizing Client. It is important to understand that no other party can receive a Phase I ESA (except a regulatory agency if applicable). As a result, the report user must provide copies of reports to others, themselves. Similarly, no other parties can legally rely on the results of a Phase 1 ESA or Phase 2 ESA, without the written consent of the report user and consultant. In such a case, the consultant will prepare a reliance letter, on behalf of the user, for the additional parties.

Forward-Thinking Geologists, Engineers & Contractors!

What is the Methane Mitigation Process?

What is the Methane Mitigation Process?

The methane mitigation process entails eliminating the risk of an explosive event at a building, as a result of hazardous soil vapor intrusion. Vapor intrusion is the natural process by which underground gasses migrate upwards and into buildings. So in the case with structures built atop contaminated soils, the chemicals from the subsurface change phases from liquid-form to vapor-form, and move indoors. These gasses take the path of least resistance. Thus, the small cracks and seams which always exist within a concrete slab are the preferred migratory pathway. And because methane itself shows no coloration or smell, occupants are unaware of its build-up. Updated November 13, 2019.

Land Developers Dealing With Methane Zones

The requirement to mitigate soil vapors isn’t exactly a land developer’s favorite thing to hear. Neither is learning about a project being within a methane zone. To most developers, the methane mitigation process is understood to be timely and costly. Although, many of them do also understand that it is a non-negotiable requirement for occupant-safety. As technology improves and knowledge spreads, regulatory agencies also become more aware of the impacts on health and safety. As a result, environmental laws and health and safety regulations keep improving, to ensure a better future for America.

Methane Mitigation Zone Maps

Methane Mitigation Zone Maps

First Step – Test for Methane

Testing for methane soil gas underground might be the first step for any developer undergoing the methane mitigation process. This task generally entails drilling at a property and installing soil vapor probes for sampling. The sampling events take place over a period of 24 to 48 hours and require the oversight of a professional geologist. In fact, in some jurisdictions, the results of the methane soil test may serve to eliminate the methane mitigation requirement overall. In other cases, it helps optimize the parameters of a mitigation system, so that developers could reduce their costs and effort as much as possible, meanwhile satisfying the local agencies.

Methane Test Report Approval

Final methane test reports require submittal to the local building department or methane mitigation authority agency. These reports undergo a strict review process by the agency caseworker and may be subject to changes and revision. It is important to contract a proper methane testing company with experience in your area, to ensure that push-backs, revisions, and rejection don’t slow down the project.

Second Step – Design a Methane Mitigation Plan

A mitigation plan is the next step in building within a methane district. This is a special design process, and generally requires the input and certification of a licensed geologist or engineer. The final set of architectural and structural plans are a prerequisite for the methane mitigation process. Additionally, a copy of the geotechnical report and grading plan is helpful. The geologist will prepare a complete set of methane mitigation plans, which include all the necessary calculations and specs for contractors to build accordingly.

Methane Mitigation Plan Approval

As imaginable, methane mitigation plans need approval as well, before any building can commence. Typically, the same agency to review and approve the methane test reports will also review mitigation plans. In many cases, both of these items undergo review simultaneously. This is because mitigation plans comprise all the site-specific methane test data, to begin with.


Approved Methane Mitigation Plans

Approved Methane Mitigation Plans

Thirst Step – Build the Methane Mitigation System

Constructing a proper methane mitigation system, in accordance with building department codes and plans can be challenging. Especially when trying to schedule the work around the other job-site activities and timelines. Methane mitigation construction is a specialized area of work and requires manufacturer certification, as well as authorization by my regulatory agencies.

Fourth Step – Get a Qualified Inspector to Double-Check

In almost every jurisdiction, the oversight agency will require that a special methane system inspector oversee and approve the construction of a mitigation system. This task typically refers to as “Methane Deputy Inspection,” and requires a certification process. A deputy inspector is in charge of using his or her knowledge in the industry, to ensure, on behalf of the local building department, that a proper construction job is taking place. Deputy inspection is a crucial part of the methane mitigation process, as it remains the final step before the project can sign off. To avoid any conflict of interest penalties, the deputy inspector should have no relation, whatsoever, to the contractor on the job.

Forward-Thinking Geologists, Engineers & Contractors!

How Much Does an LADBS Methane Soil Test Cost?

LADBS Methane Soil Test Cost & Price

An LADBS Methane Soil Test cost can vary, depending on property conditions and plans for development. In fact, a proper methane test price for a standard job can range between $2,600 and $10,000. However, site-specifics can change the price on a case-by-case basis. Thus, a phone consultation is highly recommended to get a site-specific cost. Because a methane test comprises drilling, sampling, analysis, reporting and licensing, the cost does add up. Companies that offer a “suspiciously low price” typically result in rejection, change-orders, re-testing, and lawsuits. A price quote lower than $2,300 to $2,400 warrants concern. This article provides information and insight on pricing for a proper Methane Testing Report. Updated October 18, 2019.

LADBS Methane Soil Test Cost & Price

LADBS Methane Soil Test Cost & Price (creativecommonsstockphotos)

What Justifies the Price for an LADBS Methane Soil Test Cost?

Consumers must understand that Methane Testing comprises many pillars to meet the requirements of the Los Angeles Department of Building and Safety. These facets combine to complete a proper test and justify the minimum price of $2,600. Mitigation plans are not part of the testing process.

Laboratory Certifications & Professional Geologists

For instance, the company must qualify and maintain an active Laboratory Testing Agency License with the City of Los Angeles. Furthermore, the job requires multiple days of fieldwork by licensed professional geologists and drillers. The mobilization, materials and professional costs of drilling alone result in thousands of dollars.

Drilling Rigs & Sample Materials

Above drilling, there is also a requirement for these projects to include oversight and certification by a professional geologist. From the project planning stages to the soil gas sample collection and analysis, a state-certified professional must be in charge. By the standards of the City of Los Angeles, geologists, engineers, and drillers must install soil gas probes at various depths and locations, and collect samples for analysis.

Sampling & Analysis 

The analytical results of an LADBS Methane Soil Gas Test are the basis for report preparation. Following State EPA and DTSC standards, geologists perform soil gas sampling and testing from the field and in the laboratory. Analytical data is produced in tabular form, for the review of a senior geologist. This is the primary step for quality assurance and quality control.

Report Preparation

Methane reports are comprehensive and factor in many aspects of the property. For example, a methane test report can discuss historical land-use, site geology and hydrogeology, parcel characteristics, planned development, surrounding properties, and building code requirements. Moreover, the analytical results provide insight on the LADBS Site Design Level. And a professional geologist appropriately concludes and recommends per the standards of the LA City Building Codes.

Ramifications of “Suspiciously Low Cost” Reports

Many consumers complain about unethical methane soil testing consultants that “hook clients” over a suspiciously low price. According to these unhappy customers, these unethical companies typically boast about having “many years of experience,” and offer prices drastically below the competition. 

Prices Too Low = Improper Testing

Consequently, the construction project can undergo problems. In fact, disgruntled customers of these unethical consultants have mentioned insufficient “hand-drilling” methods, falsified sampling depths and fraudulent data. Ultimately, this can cause rejection by the building department, change orders, re-testing requirements and other additional work. 

Nobody Can Actually Predict or Promise Low Results

Additionally, there have been complaints about these companies “promising low results” at the time of the sale. This is highly misleading and unethical for any consultant or company to do. In fact, it is impossible for anyone to predict the results of a methane test. Typical Los Angeles Basin soils are non-homo-genius. Thus, soil and soil-gas baring characteristics are variable from site-to-site. As a result, each property can comprise different methane soil gas concentrations. And methane test results cannot possibly be predicted, even if the neighboring lot has been tested before.

In general, a methane test price quote lower than $2,400 warrants concern.

Avoid Cheap Methane Soil Test Cost

Avoid Cheap Methane Soil Test Cost (Hoomar)

Get a Site-Specific Price Estimate & Cost 

Despite the information above, Geo Forward recommends each consumer obtain a site-specific price quote for methane testing. Prices are variable as a result of property characteristics, design parameters regional geology and more. For more information, or to obtain a site-specific price quote, call (888) 930-6604 to speak with a professional geologist today.    

Forward-Thinking Geologists, Engineers & Contractors!

What is Methane Gas Testing?

What is Methane Gas Testing?

Methane gas testing is the process by which professional geologists and engineers determine the concentration of methane in vapor between soil grains, underground. Typically, this is a requirement by building departments and government agencies. In fact, the tests are mandatory in areas within proximity to oil wells, tar pits and landfills. However, the methane gas testing process can also apply to real estate due diligence investigations. For instance; testing during property transactions. Methane is also colorless and odorless. Thus, it isn’t easily detectable via the human node factor. Nonetheless, it posses a great danger for explosion when accumulating inside underground parking garages, basements and buildings above ground. Updated June 19, 2019.

Geo Forward is a Methane Gas Testing Company

Geo Forward is a leading provider of methane tests, for all agencies across the nation. For information about this process, or a price quote, call (888) 930-6604.

Methane Gas Testing Geo Forward

Methane Gas Testing Geo Forward

What is Soil-Gas?

Soil-gas is the vapor phase substance that exists within the pore spaces of soil grains underground. In scenarios where liquid phase toxins are dumped into the ground, chemicals migrate into the soil to great depths. Consequently, the liquid phase contamination can change phases, into vapors. And as a result, the vapor phase contamination can migrate even farther. The true danger about vapor phase migration is it’s ability to creep through building foundations and microscopic pathways in concrete walls. For example, a restaurant existing above a former oil well can be infiltrated with natural gas, along with other carcinogens, posing a health and combustion risk to the occupants inside.

Health & Safety

Carcinogen health risks tend to base on long-term exposure rates. However, are still material to the health, safety and well being of people. Similarly, combustion hazardous occur by the over-concentration of this flammable gas indoors. Any ignition source inside a room with methane gas above the “Lower Explosive Limit” or “LEL” can result in an explosion. These catastrophes have happened before. Thus, awareness and implementation of soil-gas testing and mitigation is a requirement in jurisdictions across the nation.

Methane Testing initially includes a shallow probe soil gas survey. Afterwards, a drilling rig is used to drill and install multiple sampling zones underground.

Methane Testing Shallow Soil Gas Probe – Photo Credit: University of Texas at Austin & Bureau of Economic Geology

Boyle Dayton Los Angeles

Boyle Dayton Los Angeles

The Boyle Dayton Los Angeles Company was a reputable manufacturer and seller of fueling pumps and standalone underground tanks, for automobiles in the early 1900s. Unlike modern gasoline service stations, the Boyle Dayton Company was a specialty manufacturer of curbside fuel station accessories. Curbside fueling stations were common in America before the demand for full service stations. In fact, curbside fueling stations were typically part of drug stores and hardware shops. And commonly fronting the major streets and roadways. The Boyle Dayton Los Angeles company had the reputation of making stylish, economic and easy-to-use standalone pumps and tanks for these curbside fueling stations. The company was in operation from approximately 1910 through 1929, on the corner of 52nd Street and Santa Fe Avenue, in the City of Los Angeles, California. The Boyle Dayton Company was a prominent part of the history of American gasoline, oil and automobile sectors.

Boyle Dayton Los Angeles UST Gas Pump

Boyle Dayton Los Angeles UST Gas Pump

Remains of Boyle Dayton

Take a walk in Los Angeles, and you will likely not think twice about the multitude of utility manways and vaults underlying the aging concrete beneath your feet. The City of Angels has undergone rebuilding and redevelopment several times since its inception, and continues to evolve to this day. Many of the metal lids and covers seen on the street are no longer in use and long forgotten. However, some may warrant a closer inspection, particularly if you are concerned about the environmental condition of a property.

Boyle Dayton Los Angeles UST Valve Manhole Lid

Boyle Dayton Los Angeles UST Valve Manhole Lid

Non-descript circular lids are seen in sidewalks across the city, with the words “Boyle Dayton Los Angeles” on them. These metal discs bear the name of a long-forgotten gasoline dispenser manufacturing company. The Boyle Dayton Company was a huge part of the gasoline service station industry, and American industrial history. Boyle Dayton Los Angeles essentially introduced factors of convenience, quality and style into their parts, much like Apple and Tesla do today. As a result, the Boyle Dayton Company history is a feature subject in automobile and petroleum museums across the country.

Curbside Fueling Stations

The world’s first fueling station was built in Wiesloch, Germany in 1888 to refill the tank of the first automobile. This station was reportedly setup at the city pharmacy during Bertha Benz’s inaugural trip from Mannheim to Pfrozheim. In the same way, pharmacies all over began selling gasoline on the side. The first fueling station made solely to sell gasoline was built in St. Louis, Missouri in 1905. With the growing rate of automobile manufacturing and ownership, curbside fuel stations became of higher demand. Consequently, new curbside gasoline stations began to appear across the United States.

The first generations of curbside fuel stations were quickly followed by full service auto fueling and repair stations. The idea for the full service station, was to create a one-stop-shop, where travelers can repair and fuel-up their cars while using the restroom, enjoying a meal and picking up road maps and tourist brochures. Consequently, the curbside fueling stations became obsolete, and the standalone gas pumps and USTs were put out of commission. According to a review of historical fire insurance maps, these replacements began as early as the 1930s. However, fueling was not a regulated service at the time. Additionally, there had been a lack of environmental impact understanding during the early dates of decommissioning. Thus many curbside station owners chose to remove the above ground accessories, leaving the underground components in place.

Boyle Dayton Los Angeles Aug 1925 Newspaper AD

Boyle Dayton Los Angeles Arizona Republic – Aug 1925

The First Drive-Up Fuel Stations

The first drive-up station opened in Pittsburgh, Pennsylvania in 1913. In fact, prior to drive-up stations, gasoline was typically purchasable at general or hardware stores. Early gas stations were powered by kerosene adapter pumps. These pumps would require hand-cranking, and could accurately measure and dispense fuel. Earliest pump models include a metal tank with wooden cabinet, and have a hand-operation suction pump. These early systems were capable of holding approximately 40-gallons of fuel at a time. Moreover, the early systems did not entail direct fueling into and automobile. Instead, the system would require a technician to dispense the fuel into a secondary container, and manually transfer it into the vehicle’s gas tank. As a result, most gasoline stations chose to store the fuel in the dispensers themselves, in effort to save time.

Boyle Dayton Los Angeles Jun 1928 Newspaper AD (2)

Boyle Dayton Los Angeles San Francisco Examiner – Jun 1928

Early 1900 Technology & Style

The Boyle Dayton Company was born in Los Angeles in approximately 1910 and manufactured a gasoline pump called the “Boyco” by 1920. The company continued operations through 1929, until agreeing to a corporate acquisition by the Wayne Pump Company. Boyle Dayton Los Angeles had a reputation for making stylish pumps that accurately measure oil and gasoline, as well underground storage tanks, lubrication pumps, and air compressors. Pumps by the Boyle Dayton Company included bolting assemblies to the ground and connections to product pipes leading to underground storage tanks directly underground. Additionally, Boyle Dayton secured a patent for an air-powered technology which increases the speed an automobile could be fueled. As a result of the innovative design, there had been a significant increase in popularity of their pumps and sales. Consequently, installations of their pumps began spreading radially outward from their home base in Los Angeles.

Although the Boyle Dayton Company was in business for a brief period of time, signs of the former gas pump and tank manufacturer exist all throughout Los Angeles. For instance, their legacy still displays in the form of small utility covers within the city walkways, and in petroleum museums.

History of Underground Storage Tanks

In the urban areas across America, underground storage tanks (USTs) became popular for both aesthetic and functional purposes. Early tanks were typically single-wall steel sheets, and under 1,000 gallons by volume. Boyle Dayton did advertise a study manufacturing process, with galvanized steel, riveting and soldering. Moreover, the tanks and pumps had glossy paint jobs, much like cars the at the time. And according to an Automobile Trader listing for Boyle Dayton Los Angeles Company, the pumps and dispensers were capable of an easy quick connection to a variety of tanks (any capacity).

Boyle Dayton Los Angeles UST

Boyle Dayton Los Angeles UST

These tanks typically comprise of three openings. One serves a purpose for ventilation piping. Another is for a filling port. And in the third place, a suction line, leading directly to the pump. Additionally, the fill pipe appears to include a strainer to prevent debris from flowing inside the tank.

An average set up of the original Boyle-Dayton pumps may include two curbside pumps on a sidewalk. Each pump would be directly connecting to a stand-alone underground storage tank. Typically, the underground storage tanks underlay the sidewalk as well. Furthermore, additional lines were likely to extend from the UST, toward an air compressor for pump operational purposes. Fill ports are typically flush with the ground surface, and directly lead to the top of the UST for easy deliveries.

Boyle Dayton Los Angeles Jun 1928 Newspaper AD

Boyle Dayton Los Angeles San Francisco Examiner – Jun 1928

City Sidewalks

Since the original Boyle Dayton Los Angeles Company pumps were located within city sidewalks, the remnant features remain in place for over a century. Especially in areas which have not undergone road-widening and redevelopment. For example, a former curbside fueling station operational in 1915, may not have sold gasoline for decades. However, there may still be an existing fuel storage tanks (UST), as well as ventilation and product lines within the sidewalk. And although these items are technically off site, the owner may still be held responsible for any environmental issues arising from the original curbside gasoline station.

In the City of Los Angeles, municipal substructure maps often denote the locations of known underground tanks in city sidewalks. Additionally to gasoline tanks in association with former curbside stations, many city buildings historically maintain heating fuel tanks in the street. Underground storage tanks in association with former gasoline fueling activities will often still have piping and access ports to the former fill pipe and former pump locations. The “Boyle Dayton Los Angeles” utility covers in age-old sidewalks indicate the prior locations of these features. Often, these underground storage tanks are unnoticeable due to having no record of the substructure or former use of the property and the lack of familiarity with the former gasoline pump manufacturer brand.

Boyle Dayton Los Angeles Jun 1921 Newspaper AD

Boyle Dayton Los Angeles Jun 1921 Newspaper Ad

Environmental Site Assessment Concerns

Remaining underground storage tank features represent an environmental concern. This is due mostly to the lack of corrosion protection and secondary containment. Despite advertisements to the contrary, the single-wall steel piping and tanks with riveted sheet metal are prone to damage and rust. Consequently, hazardous contamination compounds include gasoline, diesel, fuel, oil and metals such as lead. As a result, these substances may impact the surrounding soil, soil vapor, and groundwater.

If a property undergoes redevelopment or selling, a Phase I Environmental Site Assessment is the prudent coarse of due diligence. Environmental due diligence reports entail professionals which may identify the potential underground fuel tanks and piping. If evidence of former fueling activities are noticeable, there would be a recommendation to perform a geophysical survey. Furthermore, the existing underground storage tanks can undergo a removal and official abandonment process, under the proper permits and environmental protocol. Typically, this includes sampling oversight by a licensed Professional Geologist.

Informational Sources

Explore Pennsylvania History

Antique Trader

Los Angeles Navigate LA

Handbook of Storage Tank Systems Available Now

American Oil & Gas Historical Society

Cali Spphere – University of California

Is the Earth Around Millennium Tower Sinking

Is the Earth Around Millennium Tower Sinking?

Is the earth around the Millennium Tower sinking? Built-in 2008, the Millennium Tower in San Francisco has reportedly sunken about 17 inches into the ground surface. This subsidence is a consequence of improper geotechnical engineering design, and potential changes in the hydrogeological setting. Moreover, surveyors indicate the structure is tilting, with a difference of approximately 3 inches from side to side. At the moment, the local building and safety department states the structure is safe for continuous living. However, the rate of subsidence isn’t likely to change or stop anytime soon. Thus, expert geotechnical engineers are handling this corrective action project, and believe the foundation can be salvaged with a final solution. At this time, cost estimations for this mitigation effort range between $300,000,000 and $500,000,000. Updated October 20, 2019.

Is the Earth Around Millennium Tower Sinking?

Is the Earth Around Millennium Tower Sinking?

The Solution to the Millennium Tower Sinking

After years of testing, analysis, and surveying, geologists and engineers are now proposing an updated mitigation plan. This corrective action proposal comprises a series of retrofit piles which aim to counterbalance the sinking foundation. As a result, the geologists and drillers plan to supersede the depths of the bay area mud underlying the building, and securely tap the new piles into the underlying bedrock. Ultimately, these devices intend to stabilize the downward sinking side of the existing high rise structure. Whereas the opposite end would temporarily continue to sink. And theoretically, the tilting building should reach an equilibrium, and straighten itself within equal or lesser time.

According to an article, the executive partners at O’Melveny & Myers (Millennium Tower resident legal representation) state the geotechnical engineers are confident the latest corrective action plan will stabilize the building over time.

Demonstration cross-section of micro pile system to uplift sinking Millennium Tower

Micro Pile (Photo Cred: Vision Winter / O’Melveny & Myers +

The Geology of San Francisco

The geology of the San Francisco bay area is complex. Much like other areas, this introduces an abundance of complications and liabilities with land development projects. Bay mud is a common sedimentary deposit comprising of sand, silt, and clay. Generally, these sediments contain shallow static groundwater levels, which also keep the soil in a consistent state of saturation. As a result, bay muds have high porosity (retaining water) and low permeability (movement of water within). Furthermore, bay muds have high compression factors and low shear strength, making it hazardous for structural development. Especially within the seismically active and fault ridden area of San Francisco, California.

Subsidence and liquefaction are the typical geological hazards in association with bay mud. And static groundwater levels fluctuate as a result of precipitation, periods of drought, water pumping and de-watering activities at nearby construction sites. Consequently, the soil-characteristics of the bay mud are subject to change, when soil zones go from wet to dry. For instance, subsidence can occur when groundwater levels decline. On the other hand, liquefaction can occur when groundwater levels rise.

Bedrock underlying the Millennium Tower is approximately 200 feet below the ground surface. The corrective action proposal entails drilling and installing a series of piles into the bedrock underlying the bay mud. Moreover, these piles are likely to base another 100 to 150 feet within the bedrock it’self. As a result, drilling requirements may require approximately 350 feet of total depth at each pile location.

The Importance of a Proper Geological Assessment

The earth around the Millennium Tower sinking is a subject that truly highlights the importance of a proper geological assessment. Cutting costs on any geological engineering service can backfire greatly.

Contaminated Soil Excavation & AQMD Rule 1166

Contaminated Soil Excavation & AQMD Rule 1166

AQMD Rule 1166 applies to Southern California construction sites undergoing contaminated soil excavation. To start, AQMD Rule 1166 requires a mitigation plan.  Moreover, this report is also goes by the title “Contaminated Soil Excavation Plan.” Additionally, the rule requires air quality testing during excavation. The primary oversight agency is the Air Quality Management District (also referred to as the AQMD or SCAQMD in the South Coast). Updated February 19, 2019.

Contaminated Soil Excavation and AQMD Rule 1166 ©Dmitry_Kalinovsky

Contaminated Soil Excavation and AQMD Rule 1166 ©Dmitry_Kalinovsky

Discovering Contaminated Soil Excavation Issues

Unless a Phase 1 Environmental Site Assessment or Phase 2 Subsurface Investigation calls it out, you may be surprised to find contaminated soil at a job site. It happens from time to time. As a result, there are legal requirements for disposal and monitoring. Consequently, an environmental engineering firm should be retained to achieve proper contaminated soil excavation and AQMD Rule 1166 compliance.

In the first place, the process starts with soil sampling by an environmental consultant. Next, the consultant will prepare a waste profile and manifest. At this point, the engineering firm should also complete a mitigation plan. Some mitigation plans are site-specific. Others are for various locations. Lastly, the SCAQMD will need to approve the mitigation plan, and issue a permit to dig.

Tasks that require AQMD Rule 1166 Compliance

Per the rule, compliance is necessary for each of the following activities:

  • Removal of any underground storage tank (UST) or associated product piping.
  • Contaminated soil excavation.
  • Stockpiling and movement of contaminated soil.
  • The treatment of contaminated soil at a disposal facility.

Accordingly, there is a need to monitor disturbed soil via an organic vapor analyzer (OVA). Often times a photo-ionization detector (PID) is exemplary. Other times a flame-ionization detector (FID) may be more ideal.

Costs for Contaminated Soil Excavation

Unfortunately, we are unable to provide any general cost estimates via the internet. There are just too many variables in each project. A custom price quote is a requirement for each specific project.  However, you can expect to pay for the following items for an AQMD Rule 1166 compliant contaminated soil excavation:

  • Soil sample laboratory analysis.
  • AQMD Rule 1166 permit application.
  • Mitigation Plan preparation.
  • Contaminated soil excavation air monitoring labor.
  • Permit closure process.
Finish the Job Right and Save Money

AQMD Rule 1166 compliance is a requirement for contaminated soil excavation. Although this process is costly, the fines and penalties for violating them are more. Thus, its best to consult an proper environmental engineering firm. Moreover, a Phase 1 Environmental Site Assessment at the purchase stage is the best recommendation for staying one step ahead. If contaminated soil becomes apparent during the assessment, a proper budget can be set.


Can You Retest Methane Test of Soil?

Can You Retest Methane Test of Soil?

Is it worthwhile to get a retest methane test of soil: Generally Not. Sometimes a methane test will show high results of the hazardous soil-gas on a property. And developers will try a retest methane test to get “favorable results.” Regardless, there is a general legal requirement to still submit the original test data (whether it has higher or lower methane levels). This is a public health code concern governed by law, and delves into the matter of developer ethics. The rule is to submit the original report with the retest methane test report for the agency to review. And even when multiple reports indicate conflicting data; more than likely the agency will use the highest overall results. Thus, retesting in hopes of “favorable results” can be pointless and a waste of money. Updated July 31, 2019.

The City of Los Angeles Department of Building and Safety (also known as the LADBS agency) has distinguished methane zones and methane buffer zones. Additionally, the Los Angeles Fire Department (also known as the LAFD agency) has oversight. As a result, methane mitigation standards apply. And therefore, a methane test becomes necessary.  Other cities and counties also administer the same methane test policies. Cities like Huntington Beach have their own standards, while others may reference the LADBS policies and guidelines directly.

Retest Methane Test of Soil - Oil Fields

Retest Methane Test of Soil – Oil Fields


Interest to Retest a Methane Test

Building Safety Codes base the standard on the highest overall test results. Consequently, the LADBS and LAFD typically select a Level per the highest overall result. For Example, consider a scenario with two methane test reports by different companies. The first methane test reports Level 5, and the retest methane test reports Level 4. In this case, the agency is likely to use the highest methane test, which is the Level 5.

The Legal Requirement to Report all Methane Test Data

High levels of methane soil gas become a matter of public health concern. Anyone that has discovered high levels of methane test results, is required to obey the California Health and Safety Code and report results to LADBS and LAFD. In other jurisdictions, all potential public health hazards should also be reported to the appropriate agency for proper evaluation.

Thus, the policy entails the appropriate agency receive a copy of each methane test report, including the original and retest methane test.

What will the Agencies Decide?

Only the appropriate oversight-agency has the authority to decide what methane level a property is. One cannot guarantee whether the agency decides to accept the original report or retest methane test. For instance, in the scenario above, the decision in the matter is entirely up to the City of Los Angeles.

Methane Test Results for Properties with Oil Wells

Developers must acknowledge that properties including (or within proximity to) oil wells typically result in high-level methane mitigation systems. Thus, it is common that a Level 5 mitigation system has an appropriate level of building safety components. Accordingly, the higher results between a methane test and a retest methane test are likely to prevail. Building an appropriate level mitigation system is not just about construction costs. Its about the health safety of those who will use the building.

For more information about the inquiry and your specific property, call (888) 930-6604 and request a free consultation today.

Additional Information & Sources: 

DTSC Reporting Nonemergency Hazardous Substance Releases

EPA Groundwater & Drinking Water

EPA Risk Assessment


U.S. EPA Guidance for CH4 Landfill Gas Sampling & Testing

City of Los Angeles, Department of Building & Safety

The CH4 Zone – The Land Developer’s Guide

Methane Testing

Methane Testing Southern California

The Geo Forward team is a provider of methane testing services for all building departments in California. Geo Forward has the perquisite certifications to perform soil and methane soil gas testing projects. Additionally, we are an authorized engineering agency for the City Los Angeles Department of Building and Safety.

Methane has the chemical formula: CH4. Methane is the primary hydrocarbon gas within natural gas from soil. And natural gas additionally includes hydrogen sulfide, or H2S. In fact, hydrogen sulfide is most apparent by it’s odor, especially in association with oil fields. Furthermore, methane soil gas can exist at high concentrations in areas nearby landfills, as well as natural oil deposits.

The main hazard of CH4 in soil gas is explosion. Without proper mitigation, the combustible gas can buildup inside structures. And because methane is colorless and odorless, occupants remain unaware.

The Geo Forward team offers fast, affordable and reliable reports.  These custom reports are guaranteed to meet building department standards. Moreover, our scope of work for each soil gas survey is custom-designed to be approved during the first submission.

Methane Testing initially includes a shallow probe soil gas survey. Afterwards, a drilling rig is used to drill and install multiple sampling zones underground.

Methane Testing Shallow Soil Gas Probe – Photo Credit: University of Texas at Austin & Bureau of Economic Geology

Benefits of the Soil Gas Survey

In some cases, methane test results can omit the requirement for developers to install a costly vapor barrier.  Geo Forward reports optimize to help plan checkers, contractors, designers and developers complete projects quickly, and on a budget.  Furthermore, mitigation plan design services aid Clients eliminate the hazards of soil gas intrusion, and meet the requirements of local building departments.

Methane Zone and Methane Buffer Zone

The City of Los Angeles determined boundaries for areas that require methane testing and mitigation. These borders make up either a Methane Zone or Methane Buffer Zone.

Related Links & Maps

The Official Los Angeles Methane Zone and Methane Buffer Zone Map
The Los Angeles Department of Public Works, Bureau of Engineering
Los Angeles Department of Building and Safety (LADBS)


Forward-Thinking Geologists, Engineers & Contractors!