Understanding Environmental Acronyms {Infographic}

The field of environmental consulting seems to have an acronym for everything. Even a cursory review of an environmental report reveals a vast array of abbreviated words. Environmental acronyms are used to call out different types of reports such as a Phase I Environmental Site Assessment, which is abbreviated to a Phase I ESA, or to call out conditions that exist on a property such as RECs (Recognized Environmental Conditions). Environmental acronyms are even used to abbreviate the types of contaminants that can be found at a site, such as PCBs (Polychlorinated biphenyls) or PFAS (Per- and polyfluoroalkyl substances).

While this list is by no means comprehensive, we have compiled some of the most common acronyms you may come across in the due diligence process in an infographic, with the acronym definitions below.

Due Diligence

AAI (All Appropriate Inquiry): Term used by federal government that describes what scope of work is required to satisfy the “innocent land owner” defense.  This means that a Phase I ESA should be conducted to AAI standards.

Phase I ESA (Environmental Site Assessment):  An investigation into the history of a property to determine what the past uses where and whether chemicals were used that could have resulted in contamination at the property. The report will identify whether RECs have been identified.

RECs (Recognized Environmental Conditions): Issues identified by a Phase I ESA that require additional investigation.

NFA (No Further Action): An NFA designation signals that contamination associated with contamination has been addressed at a site with no additional cleanup or associated response activities needed.

CAP (Corrective Action Plan): The plan on how contamination will be dealt with including active remediation, engineering controls and/or land use restrictions.

Phase II ESA: An investigation to assess RECs that involves drilling soil borings to collect soil, groundwater, vapor, sediment, or surface water samples.  Monitoring wells may be installed during a Phase II ESA.

Site Investigations

AST (Above-ground Storage Tank): A storage tank that is aboveground and could be used to store petroleum products, hazardous waste, or other hazardous material.

UST (Underground Storage Tank) and LUST (Leaking Underground Storage Tank): A storage tank that is underground which usually stores fuel product and if leaking could contaminate the surrounding soil or groundwater.

MW (Monitoring Well) and TMW (Temporary Monitoring Well): A well with a small diameter drilled into the ground and used as a sampling point to monitor contamination levels in groundwater.

TPH (Total Petroleum Hydrocarbons): A measure of the total amount of petroleum contamination present, with the TPH “range” being representative of common petroleum products. Examples include gasoline range organics (GRO) and diesel range organics (DRO), amongst others.

VI (Vapor intrusion): The bucket for the volatilization to the indoor air pathway (VIAP). State and federal regulators have determined that VI is a real concern at properties contaminated with volatile organic compounds and other volatile chemicals and have developed approaches and requirements to assess whether vapor encroachment conditions (VECs) exists and to address VI to building structures, and requirements to address VI when confirmed.

GPR (Ground Penetrating Radar): Equipment used to evaluate for the presence of buried objects such as USTs, piping, and utilities.

SSD (Sub-Slab Depressurization): A vapor intrusion mitigation strategy that relies upon inducing a slight vacuum under a building foundation or floor slab using piping and a vacuum pump or blower which allow vapors to bypass the building via that system. SSD is the same concept used in many radon mitigation systems common to residential structures.

BGS (Below Ground Surface): Depth below ground. Commonly referenced when describing the vertical location of groundwater, contamination, underground storage tanks, etc.

Regulations and Resources

ASTM (American Society for Testing Materials): An organization that develops standards for all types of things including how to perform a Phase I ESA, Phase II ESA, RBCA evaluation, etc.

AUL (Activity and Use Limitation): Restrictions that limit exposure to soil and/or groundwater contamination, and/or vapor intrusion on a commercial property.  AULs are often implemented via the recording of restrictive covenants and are used for ensuring compliance with continuing obligations, or as part of regulatory closure or NFA, as approved by federal and state regulators.

EDR (Environmental Data Resources): EDR is a leading provider of environmental records and historical documentation used in preparing ESAs.

EPA (United States Environmental Protection Agency): The EPA is the regulator for federal environmental statutes and programs for cleanup, air and water permitting, waste disposal, etc.

OHSA (Occupational Safety and Health Administration): OSHA is responsible for regulating workplace health and safety regulations.

EP (Environmental Professional): A person who is a licensed professional engineer (PE) or certified professional geologist (PG) with more than three years’ experience, or a person with a degree in the discipline of engineering or science with more than five years’ experience, or a person with the equivalent of ten years of relevant experience in all phases of UST work including tank removal oversite, site assessment, soil removal, feasibility, design, remedial system installation, remediation management activities, and site closure.


ACM (Asbestos Containing Materials): Pose a health risk when inhaled as a fine dust and need to be properly abated prior to any demolition or redevelopment activity. Some examples include sprayed on fireproofing, linoleum, roofing materials, ceiling tiles, wall and ceiling plaster.

BTEX and PNAs (Benzene, Toluene, Ethylbenzene, Xylenes and Polynuclear Aromatic Compounds): chemicals that are commonly contained in gasoline, diesel, fuel oil and used oil.

PCBs (Polychlorinated biphenyls): industrial compounds which were widely used in electrical equipment.

PFAS (Per- and polyfluoroalkyl substances): A group of chemicals, comprised of over 4,000 individual compounds. Two common examples are perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA).

VOCs (Volatile Organic Compounds): Includes a variety of chemicals that easily become vapors or gases, some of which could pose health risks.

NAPL (Non-Aqueous Phase Liquid): Historically, this was referred to as “free phase” where pure petroleum product may be present in the soil pores or “free product” is when the pure petroleum product reaches the groundwater table and floats on the water.  There are three NAPL conditions, including Residual NAPL (least amount of NAPL), Mobile NAPL (typically present as free product on groundwater), and Migrating NAPL that is observed to spread or expand (worst NAPL condition).

LBP (Lead Based Paint): Still found in older properties and need to be abated prior to demolition or redevelopment.

PPB (Parts Per Billion) and PPM (Parts Per Million): Concentrations of chemicals in soil or groundwater can be expressed in ppb or ppm.

RBCA (Risk Based Corrective Action): A process defined by ASTM that allows for site specific assessment of a property to determine the nature and extent of contamination and how that contamination should be dealt with based upon contaminant pathways (i.e. drinking water, vapor intrusion to indoor space, direct contact, etc.) that would result in a receptor (person, surface water, etc.) being exposed to the contamination.  A RBCA evaluation could result in having to actively address the contamination (i.e. excavate, install a remediation system) or being able to leave contamination in place with engineering controls and/or land use restrictions.

RBSLs (Risk Based Screening Levels): Calculation of chemical and exposure pathway specific screening levels below which no additional regulatory attention is needed.

VISLs (EPA Vapor Intrusion Screening Levels):  EPA recommended thresholds, above which point concentrations of vapor-forming chemicals are likely to pose a health risk.

TSD (Treatment Storage and Disposal Facility): Hazardous waste and contaminated soil or groundwater must be disposed of or recycled at a facility licensed by the EPA or a state environmental agency.

Baseline Environmental Assessments (BEAs) – A Practical Guide

Baseline Environmental Assessments (BEAs) are critical tools for individuals and businesses considering the acquisition of property known or suspected to be contaminated. Under the Natural Resources and Environmental Protection Act (NREPA) of 1994, BEAs provide a pathway for new owners or operators to avoid liability for pre-existing environmental contaminations. This guide will explain the concept,…

Empowering Communities: A Guide to EPA’s Brownfields Assessment Grants

Brownfields Grants, administered by the Environmental Protection Agency (EPA), are intended to empower communities to reclaim and revitalize sites that are hindered by contamination, or have the perception of contamination, and play a pivotal role in community rejuvenation. Assessment Grants serve as a crucial financial resource to support a wide array of activities focused on…

A Day in the Life of Steve Price

PM Environmental’s Principal and Vice President sits down with us to provide a glimpse into his role, as well as share some advice for ethical behavior. Q: Name, Title, Location:  Steve Price, Principal and Vice President, Lansing, Michigan. Q: Tell us a little about your role and what you do. My role is pretty unique…