Opioids: Adding to the Discussion on Safety Concerns for First Responders

Authors: Peter B. Harnett, MS, MPH, CIH, CSP and Mary E. Greenhalgh, MPH, CIH of COEH


Several recent health and safety publications include articles addressing proper first responder actions for illicit opioid operations as well as safety considerations when the first responder arrives to assist an overdose victim or enters an enclosed environment where potent narcotics are present. (The term “opioid” is used here to capture opiate derivatives such as morphine and heroin as well as synthetic and semi-synthetic narcotics including fentanyl and fentanyl analogs.) In the above scenarios, the first responder and/or team should have Narcan™ (naloxone) on hand as an antidote and have prior detailed training in its administration. The first responder should also have on appropriate personal protective equipment (PPE) that may include dermal and respiratory protection. Proper PPE determinations are difficult to make. NIOSH is one of the Federal agencies that continues to develop guidance on PPE decision-making for opioid first responders.

Many of these articles correctly point out that fentanyl is approximately 50 to 100 times more potent than morphine and that carfentanil is approximately 10,000 times more potent than morphine with regard to analgesic (relief of pain) capability. The potencies and relative potencies will differ based on routes of exposure. For example, inhalation and to a lesser extent dermal represent the most likely routes of exposure for a first responder. There is limited information on potency of fentanyl analogs by inhalation and even less information on inhalation or dermal potency for carfentanil.

Below, additional information is provided on two items that are important additions to the opioid first responder discussion.


  1. Emphasis on Impairment Rather than Lethal Dose

Many of these communications emphasize lethal doses (multiple microgram quantity range for fentanyl analogs and milligram quantity range for morphine), but it is more important to address airborne or surface concentrations that result in an impaired response since it will be more common that the first responder is exposed at levels appreciably less than fatal doses. Exposure of a first responder at levels at or below known therapeutic levels can still result in unclear thinking, delayed response time, and increased likelihood of a trip or fall. In the case of an illicit drug operation, if those involved in the illicit operation are present, any of these occurrences are likely to increase the chance of a fatality.  Even when the illicit operators are not present, serious injury can result from a fall or poor judgment handling weapons that were left behind.


  1. Carfentanil, Increasing Concern for the First Responder

Carfentanil is being added to street drugs in recent years. It was first discovered in seizures of illicit drugs in eastern Europe in 2012. By 2016, carfentanil seizures had occurred in many other countries in Europe and North America. Based on statistics from July to December 2016 for ten states that analyze for specific fentanyl analogs, 7.6% of the ~5,200 opioid fatalities tested positive for carfentanil with Ohio reporting 17.3%. (CDC, November 2017).[1] In a recent study (Minkowski et al, 2012)[2] with fifteen naïve (non-user) volunteers, carfentanil was administered intravenously (iv) at 0.019 mg/kg. Dizziness was reported in 60% of the volunteers. For an 80-kilogram adult, this is equivalent to 1.5 micrograms carfentanil dose (iv).  If carfentanil is similarly potent by inhalation, many first responders may be at significant risk whenever carfentanil is present. This is particularly a concern if the response is in an enclosed space such as a car or illicit opioid operation and carfentanil is present in a solid formulation such as a powder.


[1] Deaths Involving Fentanyl, Fentanyl Analogs, and U-47700 — 10 States, July–December 2016, CDC, November 2017. https://www.cdc.gov/mmwr/volumes/66/wr/mm6643e1.htm

[2] Minkowski, C. P., Epstein, D., Frost, J. J., & Gorelick, D. A. (2012). Differential response to IV carfentanil in chronic cocaine users and healthy controls. Addiction Biology, 17(1), 149-155.


Value of Corporate Internal Occupational Exposure Limits (OELs)

Authors: Mary E. Greenhalgh, MPH, CIH and Peter B. Harnett, MS, MPH, CIH, CSP of COEH

The Occupational Safety and Health Administration (OSHA) recognizes that many of its Permissible Exposure Limits (PELs) are outdated; the majority have not been revised since first adopted shortly after the OSHAct of 1970, and are based on research from the 1950s and 1960s.  New scientific information and workplace experience have not been incorporated, resulting in PELs inadequate to protect worker health. In 1989, efforts to revise existing PELs and adopt PELs for additional chemicals in a single rulemaking were challenged by industry and labor groups, and the PEL update was ultimately vacated by the Eleventh Circuit Court of Appeals in 1992. The Court found that OSHA had not adequately demonstrated that each PEL would eliminate significant risk while being economically feasible for each affected industry.

The unfavorable PEL culture since the 1992 decision has made it extremely difficult for OSHA to develop initial PELs for many hazardous chemicals commonly handled by US workers. Since 1992, OSHA has successfully revised a small number of PELs using traditional rulemaking processes – for example, methylene chloride (January 1997), and silica (March 2016).  However, the majority of PELs remain outdated and inadequate to protect worker health and most chemicals do not have a PEL.  In the meantime, other technical, professional and government organizations have published new or updated exposure limits.  Some forward-thinking companies supplement this by developing their own internal occupational exposure limits (OELs) based on current science, for chemicals without formal PELs.  Developing and implementing these internal OELs protect not only the company’s own employees from exposure, but when supplied to and used by their customers, reduces the company’s potential liability in future litigation brought by customers or their employees.  Companies practicing prudent product stewardship including developing and providing OELs based on current science protect themselves, their shareholders and their downstream customers.


COEH works with chemical and pharmaceutical companies developing and revising internal occupational exposure limits. Please contact 908 310-2127 or harnett.peter@gmail.com if you would like to know more about COEH’s capabilities.

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)  https://webportal.aiha.org/Purchase/ProductDetail.aspx?Product_code=d1edd7dd-fe5c-df11-ba2b-005056810034

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.



What do you do if you’re confronted with a plaintiff who alleges they were harmed by a chemical exposure, but exposure data do not exist?

Author: Peter B. Harnett, MS, MPH, CIH. Peter founded COEH in 1992. He has conducted numerous exposure assessments and frequently works with attorneys on exposure assessment issues in toxic torts cases. Peter received some assistance on this article from Drs. David Schwartz and Giovanni Ciavarra with ISS, www.innovativescience.net

Nobody on site collected and recorded occupational or environmental data measuring air, soil, surface or ground water levels of possible chemical contaminants. Now you’re left with a big question mark: What level of exposure did the plaintiff actually experience?

Enter the scientist who begins the search for information that can shed some light on the exposure levels. The scientist will likely use the following approaches, depending on case-specific circumstances:

  • Employ models to estimate past chemical exposure based on the amount of a chemical used in an operation or the size of a spill or release
  • Research the scientific literature to uncover exposure data for a similar set of circumstances involving the specific agent or a suitable surrogate. For example, if the plaintiff is alleging injury from an airborne occupational exposure to a specific volatile organic compound (VOC) with no available data, the scientist could find airborne concentrations for a VOC with a similar vapor pressure. Based on the surrogate’s emissions rate and the spill volume in a room (for which the dimensions and ventilation rate are known), the scientist could then calculate an estimate of the airborne exposure to the specific VOC. The scientist would take into account the surrogate’s properties as well as the work area where the alleged exposure occurred.
  • Enlist the help of an expert. The right expert will be highly proficient in conducting an exposure assessment to evaluate existing data and developing an action plan to deal with a lack of historical data. The type of expert required will depend on the nature of the exposure.

Following are a few examples:

  • Airborne chemical exposure: industrial hygienist, air dispersion modeler.
  • Dispersion of soil particulates in air or volatilization of chemicals from soil to air: soil scientist, air dispersion modeler.
  • Surface water contamination resulting in ingestion, dermal contact, or inhalation: environmental scientist specializing in multimedia partitioning of chemicals from water to air and potentially air to water, or ecotoxicologists to assess data from fish or plants that may have been adversely affected.
  • Ground water contamination in which a chemical moves from soil, sediment, surface water to ground water and plume (portion of ground water containing the chemical) movement must be determined: hydrogeologist, geologist, industry-specific expert (e.g.; gas-drilling experts in the case of hydraulic fracturing contamination allegations).

To illustrate how an expert can provide key insight, let’s look at the third example, ground water contamination, more closely. A chemical agent does not distribute equally to all ground water in a given area. If the chemical was introduced to the ground water at point X and the plaintiff lives in the direction indicated by plume movement, we could expect past, present and future exposure to the chemical in the ground water if the plaintiff uses the ground water. Hydrogeologists can determine the likely levels of exposure based on the amount of the chemical introduced into the ground water, the rate of plume movement, the amount of ground water, and other factors. Geologists and drillers can play an important role in the process of defining the extent of the chemical contamination of the ground water by installing monitoring wells to determine the chemical concentration over time. These monitoring wells can provide current chemical concentrations and determine ongoing concentrations for future use.

If the scientific research and expert analysis indicate very low or no exposure to the chemical in question, the information will strengthen the defense’s case. But if the information supports the likelihood of a significant exposure, the defense may consider alternate strategies.


Unnecessary Workplace Chemical Exposures

Mary E. Greenhalgh is a Certified Industrial Hygienist. She is a Senior Industrial Hygienist with Counsel in Occupational Health, Inc. (COEH). Prior to this Ms. Greenhalgh was an OSHA Compliance Officer and was employed by an environmental health and safety (EHS) consulting firm.

Peter B. Harnett is a CIH. He founded COEH in 1992. Prior to this he worked for several EHS consulting firms and worked in biological research for MD Anderson Cancer Center.
The recent New York Times article, “As OSHA Emphasizes Safety, Long-Term Health Risks Fester” accurately spotlights many shortcomings of the current system for dealing with workplace exposure to hazardous chemicals:

• It shows a flaw in the industrial hygiene philosophy of “substitution” of toxic chemicals for less toxic ones. In the highlighted example, n-propyl bromide (nPB) or 1-bromopropane was adopted as a presumably less toxic replacement for methylene chloride, known to cause acute health effects and currently considered by OSHA a potential occupational carcinogen. However, nPB is also known to cause serious health effects, including neurotoxicity and reproductive effects. In addition, NTP recently (2013) proposed listing it as “reasonably anticipated to be a human carcinogen.”
• It shows the effects of OSHA’s focus on the quicker safety inspections rather than the more time-consuming, labor-intensive health inspections that often involve months of investigation. OSHA is a relatively small agency with a small budget, and as long as OSHA and its inspectors are evaluated based on the number of inspections they complete, the preference for quick safety inspections will be difficult to change and chemical overexposures will continue to go uninvestigated.
• It highlights the effects of regulating one chemical at a time, and the effects of the lack of a coordinated interagency approach to regulating chemicals. The EPA’s emphasis on moving away from ozone depleting chemicals led to the shift from use of 1,1,1-trichloroethane (TCA) in glues used by the foam cushion industry to use of methylene chloride. This was followed by strict OSHA regulations that addressed methylene chloride, driving employers toward use of other chemicals, in this case nPB, unregulated by OSHA.

However, the article paid little attention to the most basic problem: overexposure of workers to a known toxic chemical when simple ventilation improvements and/or requiring use of appropriate respirators could provide improved protection. The solution to the problem is well-known but motivation to implement it is lacking. OSHA’s weak fines will not provide an incentive to implement controls that may be more costly than paying the fines for conducting business as usual.

Companies are better served by a strong OSHA. Many of the smaller companies do not have occupational health and industrial hygiene capability. Additionally a large portion of these small companies fail to adequately share chemical hazard information with their employees often because they do not understand the chemical hazard information and/or lack the expertise to communicate the hazards to employees. The result can include employees, who were unnecessarily harmed by avoidable chemical exposures and chemical manufacturers of the(se) chemical(s) often become defendants in toxic torts cases. The chemical manufacturers may provide adequate hazard communication on their chemical products, but these are not adequately communicated to employees.

The cost to our workers’ health and well-being and (avoidable) toxic torts litigation are not acceptable. By undertaking this compelling investigative story, the New York Times took a first step in the right direction in highlighting the issue of OSHA’s failure to address hazardous chemical exposure in the workplace.

Reasons to Support and Approaches for Personal and Site Perimeter Air Sampling at Natural Gas and Oil Hydrofracturing Sites

Author: Peter B. Harnett, MS, MPH, CIH

Why conduct personal air sampling?

The OSHA standard 29 CFR 1910.1000 “Air contaminants,” effectively requires air sampling to determine compliance with materials for which OSHA has standards. OSHA does have standards for particulates, crystalline silica, nitrogen dioxide, and several volatile organic compounds (VOCs) some of which are known to be present on natural gas and oil hydrofracturing sites.

Personal air sampling needs to be performed for crystalline silica (NIOSH evidence already indicates common exceedances of OSHA standards for crystalline silica at hydrofracturing sites.) It is possible that other OSHA standards for particular compounds or particulates may also be exceeded. It is important to perform personal air sampling to meet OSHA requirements and more importantly to determine if there are problematic levels of air contaminants that employees are exposed to onsite.

Selection of appropriate respiratory protection is based on personal air sampling results. It is difficult for an employer to justify respiratory protection selection without personal air sampling results.

NIOSH is already involved in performing personal air sampling at hydrofracturing sites and has demonstrated exposure concerns for crystalline silica. Mr. Eric Esswein at NIOSH indicates that aside from crystalline silica, air sampling is indicated for diesel particulates, particulates, nitrogen oxides and VOCs. OSHA is likely to act on these data and make visits to hydrofracturing sites with the purpose of identifying health and safety issues on the sites. (Crystalline silica is already listed on OSHA’s National Emphasis program.) The employers’ best interests are served by developing an understanding of personal air contaminant exposures prior to OSHA visits.

Perimeter air sampling is useful for several reasons. The information can provide some realistic estimates of the site’s offsite contribution to air quality. The results of the perimeter air sampling data can be utilized in models to estimate air contaminant levels at offsite locations. Additionally, local residents are likely to be pleased that site operators took the time and resources to determine the air contaminants and concentrations that could move offsite and potentially affect residents.

Information stage

An employer should initially perform area air samples to characterize the degree of exposure to contaminants for different site activities. With this information the employer can direct personal air sampling efforts to employees more likely to show elevated exposure to some onsite air contaminants.

Some likely personal air exposures exist for crystalline silica (Sand is used as a proppant.), nitrogen oxides (diesel pump exhaust), VOCs (wells and several onsite activities), particulates including PM2.5 fraction (diesel pump exhaust) and inhalable portions (diesel pump exhaust). There has been a great deal of recent press about the carcinogenicity of fine diesel engine exhaust largely resulting from the World Health Organization’s International Agency for Research on Cancer’s June 2012 conclusion that diesel engine exhaust is a human carcinogen.

For site perimeter monitoring use real-time instruments, e.g., TSI DustTrak with particle size cutoff limits to determine particulate levels and the HNU Photoionizer or equivalent for volatile organic compounds (VOCs). Choose multiple locations on the site perimeter for these measurements, because wind direction and speed change, distance from site activities… show intraday and interday variability. For planning purposes local meteorological data patterns should be useful for approximations of cardinal wind direction, wind speeds, etc. during particular time periods through the year.

The perimeter monitoring data should then be analyzed to determine likelihood of potential employee exposure issues based on area samples proximate to onsite activities and potential community exposure issues based on site perimeter work.

Actual sampling

The selection of personal samples should be based on area air samples results. If elevated personal air concentrations of crystalline silica, particulates, nitrogen oxides and/or VOCs are found, it is important that employees wear appropriate respiratory protection to maintain exposures below applicable OSHA standards. Companies should also be exploring engineering controls and work practices to reduce employee exposure. VOC analysis should initially be performed to identify specific volatile organics present. In natural gas and oil exploration aromatic compounds including benzene, toluene, ethyl benzene and xylenes are likely to be present near the well. Additionally, these compounds each have published OSHA Permissible Exposure Limits (PELs). GC/MS analysis is recommended. Analysis of the initial personal results for VOCs will inform approaches to future VOC personal air sampling.

Perimeter air sampling with fixed sampling techniques will be used to provide more accurate and precise results than real-time measurements. For VOC analysis, GC/MS analysis should be performed to identify specific VOCs found at the site perimeter. (Elevated VOC levels will result in elevated ozone levels.) Perimeter particulate levels should initially be compared with National Ambient Air Quality Standards (NAAQS). Levels above the NAAQS may be expected downwind from onsite activities that produce dust.

The information gathered from site perimeter air sampling is a useful stepping off point for communications with local residents. Some of the residents will express concern about the site activities creating harmful air pollutants. By conducting the perimeter air sampling, it is a demonstration to the local residents that the site operators are concerned with local residents and the possibility that the movement of air contaminants offsite could pose an issue.

Some Thoughts on Exposure Assessment and Chemical Hazard v. Chemical Risk

Authors: Peter B. Harnett, MS, MPH, CIH and Mary E. Greenhalgh, MPH, CIH

Exposure assessment is defined as a process to provide answers to questions about who was exposed, exposure routes (inhalation, dermal, ingestion), frequency, length, level and duration of exposure to the chemical. Ideally, actual levels of the chemical in the exposure media are measured. Frequently, claims of exposure are made without any examination of whether exposure was possible. For example, many chemistry laboratories have sodium cyanide salt in the laboratory. An approximate fatal dose to humans is between 2 and 3-grams. A container of sodium cyanide in the laboratory is likely to be 50-grams or more. However, the simple presence of sodium cyanide in a container in the laboratory does not demonstrate any exposure to this highly toxic chemical. Although sodium cyanide is a hazard, it does not pose a chemical risk concern in the absence of an exposure.

A client of ours faced workers’ compensation payouts to employees with vague complaints, i.e., respiratory irritation, headache, pain, nausea due to alleged exposure to an alkaline aerosol. We collected approximately 500-air measurements with the majority showing “non-detectable” amounts of this irritating compound. At the work locations for the “affected” employees within the 50+ facilities visited, no levels above 10% of the only published occupational exposure limit for a workday and short-term (15-minute exposure) period were measured. It is highly improbable that such de minimus airborne concentrations could be causing health effects from inhalation or any other route of exposure. At a loss for identifying the cause of these alleged symptoms, several non-occupational physicians indicated our client’s chemical, which had just been introduced to the plant, was the cause of the person’s health complaints. The extensive air sampling data, which would not support such health claims, were of limited value in eliminating the workers’ compensation claims. The reasoning of these physicians was no more complicated than new allegations of health complaints must be associated with the “new” chemical in the plant. Again the chemical is hazardous, yet does not pose a chemical risk concern in the absence of an exposure.

In our chemophobic society, school children are often told that they should avoid exposure to chemicals. On face value, this is reasonable advice. However, there is no attempt to communicate to students that the amount of exposure to the chemical determines whether toxic effects will likely result. Many of these students continue through high school lacking any fundamental understanding of chemical risk and the role of sufficient exposure to result in health effects. The personal concerns regarding health effects due to chemical exposure are further exacerbated by better analytical techniques capable of detecting successively lower concentrations of chemicals in our environment.

We need to develop training programs to better educate science teachers on chemical hazard v. chemical risk. Namely, a chemical may be hazardous, but in the absence of an exposure, the chemical does not pose a risk to someone’s health or well-being. As more nuanced education about chemical hazard and chemical risk are provided as the student matures, we will have more adults capable of properly assessing chemical situations and with the capability to better examine news media claims regarding allegations of chemical risk. These chemical “savvy” adults will be in a position to better influence policy-makers and some of them may play roles in better scientific communication of chemical concerns through public media.

Vinyl Chloride Train Wreck Safety Assessment

This article was authored by Peter Harnetta certified industrial hygienist (CIH) who provides expertise in evaluation of environmental exposure assessments, health and safety program development, chemical risk assessments, occupational safety training programs, biosafety evaluations, consumer product health-based risk assessments, compliance audits for laboratories and other workplace settings. Peter is the founding member of Counsel in Occupational and Environmental Health (COEH).

On November 30, 2012, a Consolidated Rail Corp. (Conrail) was crossing the Paulsboro bridge in New Jersey . The train derailed and four tank cars fell off the bridge into the Mantua Creek. According to the Environmental Protection Agency (EPA), one of the tank cars released approximately 100,000 pounds of vinyl chloride into the air as vapor and much smaller amount into surface water. The nearest water intakes are estimated to be 20-miles away.

As counsel begins to address this case, it will be important to perform a careful assessment of general causation and specific causation. In this post, we summarize some of the top line information available pertaining to vinyl chloride and discuss some of the approaches and information that may be taken from a scientific and medical perspective.


What is vinyl chloride?

Vinyl chloride is a flammable gas that when polymerized forms polyvinyl chloride (PVC). PVC is a plastic used in building construction, furniture, and piping.  Vinyl chloride gas is synthesized and does not normally exist in nature. Vinyl chloride has an odor typically described as mild and sweet. The human nose detects vinyl chloride at approximately 3000 ppm and greater in air. Vinyl chloride is heavier than air.


Routes of exposure

Air Exposure

The most likely potential route of exposure for vinyl chloride under these circumstances is inhalation. Vinyl chloride is rapidly absorbed into the body after inhalation.

Water and Soil Exposure

Although some vinyl chloride likely entered surface water, the closest water intake for drinking water is estimated to be 20 miles away. Due to the high vapor pressure of vinyl chloride (in conjunction with its low water solubility) any vinyl chloride that made its way into surface water will be minimal after the 20-mile trip. Additionally, there will be tremendous dilution of the vinyl chloride concentration as it combines with a much larger body of water on this 20-mile trip.

We found no evidence that vinyl chloride would have been absorbed into the soil, which further minimizes concern that vinyl chloride would move from soil to the groundwater below. Although this is still a possibility, again the high vapor pressure of vinyl chloride would act to minimize the amount of vinyl chloride at the soil surface and hence minimize the amount that could reach groundwater.


Some skin contact with vinyl chloride was likely among the downwind residents located proximate to the release. Dermal absorption of vinyl chloride is described as negligible by the Centers for Disease Control (CDC).

Health Effects 

Acute Exposure

Less than 40 people sought medical treatment on the morning of November 30, 2012. If these individuals were exposed to elevated levels of vinyl chloride for a short period of time, this is referred to as an acute exposure. High acute exposures (levels over 10,000 ppm) have been linked to adverse events such as dizziness and headaches. At levels above 25,000 ppm for a few minutes or more, loss of consciousness and death can occur.

Animal studies at ~25,000 ppm in air indicate there can be damage to the liver, kidneys, heart and lungs and these levels have also been linked to interference with blood clotting.  Other reported effects can include effects on the lymphatic and central nervous systems.

Symptoms reported by residents seeking medical care shortly after the vinyl chloride release included irritation to eyes, skin and respiratory tract. However, since most of the vinyl chloride entering a person’s body is eliminated within 24-hours, it is very unlikely that these rather mild acute symptoms would continue beyond a few days. From an initial review of the reports, the symptoms appear to represent lower level exposures over an acute time period (e.g., exposure to levels well below 10,000 ppm for minutes or hours).

Chronic Exposure

Chronic low level exposure to vinyl chloride in the workplace has been shown to increase the risk of developing a rare form of liver cancer, angiosarcoma. Vinyl chloride levels required for the development of angiosarcoma of the liver appear to be between 10 ppm and 100 ppm and the period of exposure necessary for this cancer induction approaches a working lifetime (40 years). OSHA’s current 8-hour workplace exposure limit (i.e., the amount of vinyl chloride to which an occupational worker can be exposed for a working day) is 1 ppm.  This exposure level is generally considered to protect employees working with vinyl chloride from developing angiosarcoma of the liver.

Occurrence of other cancers has also been linked to vinyl chloride exposure (e.g., brain cancer, lung cancer, and some cancers of the blood); however, any association with these other cancers is speculative at best.

There have been some excellent government reviews of the health effects of vinyl chloride, including one by ATSDR and another by EPA.

What Data May be Available for Evaluation

It is likely that some air sampling data for airborne vinyl chloride levels were collected shortly after the spill and in the hours and initial days after the release. Wind speed, wind direction, temperature, humidity and weather stability will all be very important factors to evaluate and factor in to any analysis of the levels obtained. Details about each of these variables should be available from nearby meteorological stations and may suitably represent the conditions at the time of the vinyl chloride release and hours after the initial release. This evaluation will permit air dispersion modeling and possible incorporation of empirical air sampling data to predict concentrations at specified distances from the release site.

Several biological exposure indices can be useful in the determination of approximate levels of vinyl chloride following an exposure.  The medical records for each plaintiff should be studied to determine if any determinations of vinyl chloride levels in breath were performed at the hospital or treatment center shortly after the arrival of residents alleging health effects.

A metabolite of vinyl chloride, thiodiglycolic acid, can be measured in the urine as an estimate of prior vinyl chloride exposure. As with the inhalation test, this test should occur within a few hours of the resident’s arrival at the hospital. The amount of thiodigylcolic acid in the urine should provide a qualitative (or at best a semi-quantitative) estimate of vinyl chloride exposure.

Finally, if some vinyl chloride binding to genetic material occurred this can be determined through the collection of blood samples or other body tissues. This test can be done in the future and does not need to be performed at the time of hospitalization.



With air sampling data, air dispersion modeling, and medical reports it should be possible to approximate the level of vinyl chloride exposure to nearby residents. At the present time, we do not have any information about the air sampling data or whether any biological exposure monitoring was performed shortly after admission of the residents.

If the resident exposure is assessed to be an acute low level exposure, ATSDR/CDC indicates that with such an exposure  “… a person recovers quickly [and] is unlikely to [have] delayed or long-term effects.”