Preparing an EHS professional for litigation

Authors: Peter B. Harnett, MS, MPH, CIH, CSP and Mary E. Greenhalgh, MPH, CIH of COEH. Assistance provided by Dr. David Schwartz of Innovative Science Solutions (ISS).

If you’re involved with a toxic tort or environmental contamination case with alleged exposures to chemical, biological or physical agents, an Environment Health & Safety (EHS) professional may be just the expert you need to bolster your case.

In the toxic tort case, the plaintiff may allege that past exposure has caused the current illness or disease. In the environmental case, alleged contamination of air, soil, sediment or water may pose a current or potential concern for future illness or disease among nearby residents. The first step is to determine which type of EHS professional could provide valuable insight and expertise in a toxic tort or environmental contamination case. Described below are 3 types of EHS professionals and the relevant skills they can bring to the case:
Industrial hygienist- Assess airborne chemical and biological sampling data and evaluate data gaps in this information; perform exposure assessments to estimate likely exposure range in the absence of exposure data; use risk assessment tools to estimate the increased risk of a toxic endpoint as the result of chemical, biological or physical agent exposure.

Toxicologist- Perform literature searches and review to determine common illness or disease concerns associated with exposure(s); like the industrial hygienist, the toxicologist may also perform risk assessments based on real exposure data or estimations of exposure.

Soil scientist and/or geologist- Examine and review concentrations of soil contaminants; help to determine whether these concentrations are “problematic” based on other how “clean is clean” decisions in area. Soil contaminants may pose an exposure concern as the result of migration into surface or groundwater.

The attorney should be prepared to provide the EHS professional with all available sampling data. Explain your initial assessment of the case to the EHS professional, then begin to query the EHS professional to gain additional information.

  • What are your general thoughts about the case based on what I have discussed with you?
  • Can you describe what additional information we need to better address the claim that the plaintiff was exposed to the contaminant?
  • Do you feel the indicated exposure data are adequate? The EHS professional will need to identify exposure gaps and use best available professional practices to estimate what the exposures would have been. For example, the industrial hygienist may be able to perform air dispersion modeling to better assess occupational or environmental exposure to a chemical, biological or physical agent. The hydrogeologist may be skilled in using groundwater modeling to determine where a chemical plume may migrate and the concentrations likely to occur as the chemical migrates in groundwater.

Once likely exposure levels to the contaminant have been established, the toxicologist is typically tasked with the question of whether this level of exposure can result in the alleged illness or disease. This use of a toxicologist may not be necessary if there is plenty of available literature indicating that exposure to this particular contaminant results in the development of an illness or disease. However, this is often complicated by the presence of multiple contaminants, the nature of the alleged exposure (acute vs. chronic; episodic vs. continuous exposure, etc.). If it is determined that a toxicologist is necessary, it is worthwhile to share the exposure information. The toxicologist should do a preliminary literature review to develop an opinion about contaminant exposure levels and the likelihood that those exposure levels could result in the illness or disease. Here are some possible questions for the toxicologist.

  • Is there evidence indicating that the exposure levels could result in the indicated illness or disease? If so, what is the strength of that evidence?
  • Are you aware of other contaminants that can cause this same illness or disease?
  • Is there any evidence that our plaintiff may have been exposed to sufficient levels of these other contaminant(s) to develop the indicated illness or disease? (If an industrial hygienist were involved in reviewing prior occupational exposure records, this will be useful information to share with the toxicologist.)

After review of the exposure information and its relation to the indicated illness or disease, a risk assessment may be warranted. A quantitative risk assessment will utilize established methods to determine whether the exposure meets or exceeds an established exposure level that may increase the plaintiff’s chance of developing the illness or disease. Develop familiarity with the risk assessment process that was utilized by asking the following:

  • What established methods did you use to perform the risk assessment?
  • What factors were used to determine levels of exposure to the plaintiff? It is unlikely that “plaintiff-specific” information will be available for some factors. These factors could include respiration rate, estimate of surface area exposed to contaminant, body mass…
  • Explain the results of your quantitative risk assessment.
  • Based on your quantitative risk assessment, what estimate would you provide regarding the potential of this exposure to result in the plaintiff’s illness or injury?


Once the risk assessment has been performed and you determine that it is helpful to your case, you will want to communicate that risk in a way that will be understandable to lay people. This will be both a defensible, technical description as well as involve the use of simple demonstrative exhibits that help to make the risk assessment understandable. What factors were used to determine levels of exposure to the plaintiff?  Based on your quantitative risk assessment, what estimate would you provide regarding the potential of this exposure to result in the plaintiff’s illness or injury?


After you have developed all of the elements listed above, you will want one of your EHS experts to function as a wrap-up expert. In this role, he will compile all of the testimony you have developed and come to an ultimate conclusion that is helpful to your case.


Useful links for attorneys working with EHS professionals:

1.   Regulations, guidance

 National Primary Drinking Water Regulations

Tables including EPA’s Maximum Contaminant Levels (maximum level of a contaminant allowed in drinking water) and Maximum Contaminant Level Goals (level of a contaminant below which there is no known or expected health risk) for microorganisms, chemicals and radionuclides.

OSHA Permissible Exposure Limits (PELs)

OSHA enforceable exposure limits to protect workers against health effects of exposure to hazardous substances.

National Ambient Air Quality Standards (NAAQS)

EPA air standards for six “criteria” pollutants considered harmful to public health and the environment.  Primary standards provide public health protection, including protecting the health of “sensitive” populations such as asthmatics, children, and the elderly. Secondary standards provide public welfare protection, including protection against decreased visibility and damage to animals, crops, vegetation, and buildings.

Elemental Concentrations in Soils and Other Surficial Materials of the Conterminous United States

Concentrations of 50 chemical elements in U.S. soils.

Permissible Exposure Limits Annotated Tables

These tables include the mandatory OSHA Permissible Exposure Limits (PELs) annotated side-by-side with other selected occupational exposure limits, including the Cal/OSHA PELs, the NIOSH Recommended Exposure Limits (RELs) and the ACGIH® TLVs®s. The tables list air concentration limits, but do not include notations for skin absorption or sensitization.

ACGIH Threshold Limit Values and Biological Exposure Indices

Recommended occupational exposure guidelines for >700 chemical substances and physical agents and biological exposure indices for 80+ chemical substances.

NIOSH Pocket Guide to Chemical Hazards

Key industrial hygiene information, including exposure limits, exposure routes, measurement methods, protective equipment, etc., on several hundred chemicals.

 2.   Useful references, texts

Hawley’s Condensed Chemical Dictionary

Compendium of technical data and descriptive information, including properties, hazard and use, on thousands of chemicals.

Hyperstat Online Statistics Textbook

 Analytical Chemistry Basics

Introduction to fundamental concepts and methods of analytical chemistry

The Occupational Environment: Its Evaluation, Control and Management (3rd edition)

Essential core reference for the occupational safety and health/industrial hygiene field.  Includes, among other topics, comprehensive information on hazard recognition and evaluation, air monitoring, exposure and risk assessment, physical agents, controlling the occupational environment, and program management.

Principles of Industrial Hygiene

Johns Hopkins Bloomberg School of Public Health free online industrial hygiene course providing an introduction to the field of industrial hygiene and occupational health.

Casarett & Doull’s Toxicology: The Basic Science of Poisons, 7th edition, 2011

Authoritative reference text on the key concepts in toxicology.

Integrated Risk Information System (IRIS)

An EPA database containing EPA’s position on the potential adverse human health effects that may result from chronic exposure to chemical substances found in the environment. Includes the reference dose for noncancer health effects resulting from oral exposure, the reference concentration for noncancer health effects resulting from inhalation exposure, and the cancer assessment for both oral and inhalation exposure.

ATSDR Toxicological Profiles

ATSDR toxicological profiles succinctly characterize the toxicologic and adverse health effects information for individual hazardous substances. Each peer-reviewed profile identifies and reviews the key literature that describes a hazardous substance’s toxicologic properties.

 Hazardous Substance Data Bank

A peer-reviewed data file focused on the toxicology of potentially hazardous chemicals, including information on human exposure, industrial hygiene, environmental fate and emergency handling procedures.

Environmental Acronyms

Industrial Hygiene Acronyms

Groundwater and Wells by Fletcher G. Driscoll

Comprehensive groundwater reference book describing aquifer properties, the hydrologic cycle, movement of water, well hydraulics, and water well design, construction and testing.