Understanding exposure is essential to understanding whether the toxic properties of chemicals have been or will be expressed. This presentation provides a view of how the magnitude of exposure comes to be understood.

1. Michael D. Klein, P.E., CHMM
06/26/2012

2.  Topics that will be covered include
 Specialty experts.
 Experts and the science of exposure to chemical
hazardous materials.
 What steps an expert takes to evaluate a chemical
exposure
 Sample case study

3.  You have located, screened, and selected an expert
whose credentials are:
 above reproach
 has the education, training, and experience
 who can withstand a Daubert challenge
 whose particular skills are what are needed for the
case
 who has communication skills

4.  Before signing that engagement letter, you the
litigator should think through what will be required for
the case.
 Does the case require a
 workhorse?
 a show horse?
 or a racehorse?
 Is the case dependent largely on the quality and
sophistication of calculations and analysis?
 Does counsel need a polished courtroom
appearance?

5.  Does the expert need to be capable of translating
arcane formulae and calculations into opinions that
will not put a jury panel of mere mortals to sleep?
 Does the case demand someone with expertise in a
highly specialized area?
 Does the expert need to be capable of hitting top
speed when emergencies arise or timelines are
tight?

6.  The litigator and the expert must define the facts and
assumptions — the “givens” — on which the expert
will base the evaluation of a chemical exposure.
 These facts and assumptions represent the
foundation of the expert’s opinion.
 An expert who undertakes an evaluation of a
chemical exposure without having facts and
assumptions clearly defined and articulated is on a
very slippery slope.

7.  Litigation involving the chemicals said to pose
excessive risks to health requires litigants to present
evidence regarding exposure.
 Exceeding regulatory standards
 Understanding the exposure is essential to
understanding whether the toxic properties of
chemicals have been or will be expressed in humans
or the animal population.
 Exceeding levels that lead to adverse health effects

8.  Claims of toxic tort or product liability generally
require expert testimony in
 Medicine
 The sciences of epidemiology and toxicology
 The nature and magnitude of the exposures incurred
by those alleging harm

9.  Litigation involving the chemicals said to pose
excessive risks to health requires litigants to present
evidence regarding exposure.
 Where the magnitude of exposure is an important
component of the needed evidence, and if that
magnitude is not a simple question of fact, then
expert testimony will be important.

10.  Exposure science is not yet a distinct academic
discipline.
 Initially, exposure assessment was typically practiced
by toxicologists and epidemiologists.
 As the breadth and complexity of the subject began
to be recognized scientists and engineers are now
necessary to provide scientifically defensible
assessments.

11.  The engineer and scientist is a grouping of experts
who can provide expertise as to the properties of
chemicals
 How they behave and undergo change in different
environments
 The methods available to identify and measure
chemicals in products and in the environment
 Their training, education and experience.
 The necessary foundation of an expert to provide
scientifically defensible assessments.

12.  The expert’s job goes beyond merely stating
conclusions.
 He or she must be comfortable articulating the basis
for calculations and conclusions.
 This will require the ability to “deconstruct and
reconstruct” the big picture into all its component
parts and computations.
 The expert will not simply be called on to opine
based on a static set of facts. He or she must be
able to master the event chronology in the case.

13.  Exposure science is the study of how people can
come into contact with (are exposed to) chemicals
that may be present in various environmental media
 Air
 Water
 Food
 Soil
 Consumer products of all types
 They evaluate the amounts of those chemicals that
enter the body as a result of these contacts.

14.  Human beings are exposed to natural and industrial
chemicals from conception to death.
 Almost all chemicals can become harmful if
exposures exceed certain levels.
 The exposure expert brings understanding as to the
magnitude and duration of exposures to chemicals
 This is critical to understanding their health impacts.

15.  Exposure scientists also study whether and how
those amounts change over time.
 The goal of exposure science is to quantify those
amounts and time periods.
 The quantitative expression of those amounts is
referred to as a dose.
 Ultimately the dose incurred by individuals or
populations is the measure needed by health experts
to quantify risk of toxicity.
 Exposure science does not typically deal with the
health consequences of those exposures.

16.  Exposure assessments can be directed at past,
present, or even future exposure
 They can be narrowly focused
 One chemical
 One environmental medium
 One population group
 They can also be very broad in scope
 Many chemicals
 Several environmental media
 Several different population groups

17.  Oil and gas recovery operations utilize the process
of Hydraulic Fracturing.
 Perform a chemical exposure evaluation of the
operations.
 Information that is required to perform it.
 Results obtained from a chemical exposure
evaluation.
 How the results are used.

18.  The method used to make hard shale rock more porous.
 Allows gas shale to flow through the fine grained, organic-rich,
sedimentary rock formations to the wellbore.

19.  Shale gas is present across much of North America in basins of both
extreme and moderate size. Some of the major shale reserves
include:
 Marcellus (Pennsylvania, New York,
Ohio, West Virginia, Kentucky)
 Bakken (North Dakota, Wyoming)
 Haynesville (Texas, Louisiana)
 Barnett (Texas)
 Eagleford (Texas)
 Fayetteville (Arkansas)
 Antrim (Michigan, Illinois, Ohio)
 Woodford (Oklahoma)

20.  The Marcellus Shale
is known as the
Saudi Arabia of
Natural Gas.
 The US Geological
Survey estimates
500 trillion cu ft of
natural gas in
Marcellus alone.

21.  Until recently shale gas could not be cost
effectively extracted.
 Two factors came together in
recent years to make shale gas
production economically viable:
• Advances in horizontal drilling
• Advances in hydraulic fracturing

22. By drilling and casing a well for the extraction of the
natural gas
 producers drill into the earth several thousand feet
until they reach the natural gas reservoir
 steel casings are inserted to a depth of 1,000 to
3,000 feet
 the space between the casing and the drilled hole
is filled with cement to stabilize the well and prevent
any leakage
 the cement sets
 this process is repeated, using a series of s
successively smaller casings until the reservoir
is reached
 depths reach distances of 6,000 to 10,000 feet

23. Once drilling and casing is complete
 3 to 5 million gallons of
water, mixed with sand and
chemical additives, are
pumped into the wellhead
at high pressure, creating
cracks in the rock beds
 the hydraulic fracturing
mixture is 95% water,
4.5% proppant, and
0.5% chemical additives

24. Once drilling and casing is complete
 Proppant is a material, such as grains of sand, ceramic,
or other particulates, that prevent the fractures from
closing when the injection is stopped.
 Fracturing fluid formulas vary slightly among production
sites in accordance with the unique requirements of each
site’s geology.
 The fracture width is typically maintained after the
injection by introducing a proppant into the injected fluid.

25.  Shale gas extraction using the process of
hydraulic fracturing environmental and human
health concerns possibly may include the
 Potential mishandling of solid or liquid toxic waste
 Potential risks to air quality
 Potential contamination of ground water
 The unintended migration of gases and hydraulic
fracturing chemicals to the surface within a given
radius of drilling operations

26.  Exposure assessment is generally intended to
answer the following questions:
 Who has been or could become exposed to a specific
chemical(s) arising from one or more specific sources?
 Is it the entire general population, or is it a specific
subpopulation?
 What specific chemicals comprise the exposures?
 What are the pathways from the source of the
chemical to the exposed population?

27.  Pathways include direct product use.
 Indirect pathways where the chemical moves
through one or more environmental media to reach
the media to which people are exposed.
 Air
 Water
 Food
 Soil and dust
 Understanding pathways is necessary to
understanding exposure routes and quantifying
exposures.

28.  By what routes are people exposed?
 Routes include ingestion, inhalation, and dermal
contact.
 Identifying exposure routes is important because
those routes affect the magnitude of ultimate
exposures and because they often affect health
outcomes.
 What is the magnitude and duration of exposure
incurred by the population of interest?

29.  Dose: the amount of chemical entering the body or
contacting the surface of the body, usually over
some specified period of time (often over 24 hours).
 Duration refers to the number of days over which
exposure occurs.
 Exposures can be intermittent or continuous and can
be highly variable, especially for some air
contaminants.

30.  The ultimate goal of exposure assessment is to
identify dose and duration.
 After a chemical enters or contacts the body, it can
be absorbed (into the bloodstream), distributed to
many organs of the body, metabolized (chemically
altered by certain enzymes in cells of the liver and
other organs), and then excreted.

31.  Understanding these processes is important to
determining whether and how a chemical may cause
adverse health effects.
 These processes mark the interface between
exposure science and toxicology, epidemiology, and
medicine.
 Understanding the dose is the necessary first step in
understanding these processes.

32. Questions?
Thank you for having
me!