Rachel's Democracy & Health News #846  [Printer-friendly version]
March 16, 2006


[This document is on-line with live links at 
prn_beyond_qra.060316.htm ]

[Rachel's introduction: Most environment-and-health decisions are now
made using numerical risk assessment. But this technique has fatal
flaws that cannot easily be overcome. So how can we make good

By Peter Montague

As every community activist knows, in the U.S., decisions about the
environment and human health are based on numerical risk assessments.
In a numerical risk assessment (also known as "quantitative risk
assessment") the dangers of a project are translated into numbers and
those numbers become the basis for a decision.

For example, in Camden, N.J., government officials have declared that
the dangers of living near a garbage incinerator are "acceptable"
because their risk assessment concluded that only one in a million
people living near the incinerator for a lifetime will get cancer from
breathing the fumes and soot.

This particular incinerator spews one ton of toxic lead each year (in
the form of a breathable dust) into a residential community of people
who are already stressed by low-income and racism. But risk assessors
have managed to declare this enormous quantity of a potent neurotoxin
"no problem" by considering only its ability to cause cancer. Its
ability to cause brain-damage in children has been assigned a value of
zero. This is the great appeal of numerical risk assessment -- it
allows really serious dangers and injustices to evaporate in a cloud
of numbers -- poof!

In recent years, quantitative risk assessment (QRA) has been heavily
criticized not only by citizen-activists but also by scientists; see,
for example Silbergeld 1993, Karstadt 1988 and Kriebel 2001

Seven scientific criticisms of Quantitative Risk Assessment

QRA is criticized because

(a) We are all exposed to multiple stressors all the time, and the
effects of multiple stressors are difficult or impossible to evaluate;
in many cases standardized protocols do not even exist for making the
needed assessments.

(b) The timing of an exposure can be critical. A fetus exposed to a
chemical during the 4th week of pregnancy may develop a birth defect,
but exposed to the same chemical in the 12th week may show no effects
at all. Chemical toxicity tests are too crude to reveal all such time-
dependent effects.

(c) By definition, QRA only takes into consideration things that can
be quantified, so QRA omits much that local people might consider
important. Historical knowledge, local preferences, spiritual values,
ethical perspectives of right, wrong, and justice/injustice -- all are
ignored by QRA because they cannot be turned into numbers.

(d) QRA is difficult for most people to understand, and obscure
decision-making techniques run counter to the principles of an open

(e) Politics can -- and do -- enter into QRA. William Ruckelshaus
(first administrator of U.S. Environmental Protection Agency) said in
1984, "We should remember that risk assessment data can be like the
captured spy: If you torture it long enough, it will tell you anything
you want to know."

(f) The results of a QRA are not reproducible from laboratory to
laboratory and so QRA does not meet the basic criterion for being
considered "science" or "scientific."

As the National Academy of Sciences said in 1991, "Risk assessment
techniques are highly speculative, and almost all rely on multiple
assumptions of fact -- some of which are entirely untestable." (Quoted
in Anthony B. Miller and others, Environmental Epidemiology, Volume
1: Public Health and Hazardous Wastes (Washington, DC: National
Academy of Sciences, 1991), pg. 45.)

(g) By focusing attention on the "most exposed individual,"
quantitative risk assessments have given a green light to hundreds of
thousands or millions of "safe" or "acceptable" or "insignificant"
discharges that have had the cumulative effect of contaminating the
entire planet with industrial poisons. See Travis and Hester, 1991
and Rachel's News #831.

So quantitative risk assessment stands scientifically discredited. But
we still have to make decisions. If risk assessment isn't an adequate
basis for decisions, what is?

Guidelines for making decisions under uncertainty

Back in 1993, Donald Ludwig and others offered some awfully good
advice about decision-making, in an article in Science magazine:

"Most principles of decision-making under uncertainty are simply
common sense," they wrote.

They went on: To make good decisions under uncertainty, we can

** consider a variety of plausible hypotheses about the world (in
other words, examine the available alternatives)

** favor actions that are robust to uncertainties (in other words,
ask, "What if we're wrong?" and make decisions accordingly.)

** hedge (which I take to mean, "Don't put all your eggs in one

The next 4 suggestions from Ludwig are similar to "Adaptive
Management." (See Holing, 1978; Walters, 1986; and Lee, 1993.)

** favor actions that are informative;

** probe and experiment;

** monitor results;

** update assessments and modify policy accordingly.

And finally:

** favor actions that are reversible.

As you might imagine, if these criteria were applied to the municipal
discards (aka "garbage") of Camden, New Jersey, it is unlikely that an
incinerator in a residential neighborhood would be the answer.

Other ways of gathering information

In addition to using common sense in making decisions, decision makers
can use modern techniques for gathering information, to prepare
themselves for making good decisions. Quantitative risk assessment is
one way of gaining information, but there are others. I will briefly
describe three.

1) Identify hazard, not risk

Risk assessment requires scientific knowledge of (1) the hazard posed
by a chemical (or combination of chemicals), plus (2) knowledge of how
people may become exposed, plus (3) knowledge of how the human body
will react to the exposure. In reality this information is exceedingly
expensive to collect, and therefore exceedingly rare. Missing
knowledge is assigned a numerical value and the risk assessment

A simpler approach is to stop at the stage of "hazard assessment" and
then require chemical users every few years to search for less-
hazardous alternatives. However, even this approach is not as simple
as it sounds because microbiologists are constantly learning many new
ways in which chemicals can influence living things.

Under this simplified approach, chemical manufacturers (or users)
would be given several years in which to make a reasonable
demonstration of hazard for each of their chemicals (including its
associated byproducts and breakdown products), to show that each is
neither persistent nor bio accumulative, nor carcinogenic, nor
multiage, nor disruptive of intracellular signaling (by hormones,
neurotransmitters, growth factors, cytokines, and so on), nor toxic at
low doses to growth, development, reproduction, immunity, or
neurological function. Testing would occur on multiple generations of
sensitive species of animals, unless testing on less than whole
animals can give equivalently useful and reliable results.

As you can see, even "hazard assessment" is contentious and difficult.
(Adapted from Thornton, 2000.)

2) Delphi technique.

The Delphi technique (or simply, "Delphi") has been widely used in the
medical field to try to reach consensus among experts on important
questions that entail considerable uncertainty. Delphi consists of a
series of questionnaires sent to a group of experts, who usually
remain anonymous and never meet face-to-face (thus keeping costs low).

Initially, the experts are asked an open-ended question, such as "What
are the 50 most important problems facing nurses who specialize in
cancer?" After the initial results are tabulated, a second and third
round (or more) of questionnaires are sent to the experts asking them
to rank the results of the first round. In between rounds, the experts
are given feedback on the results of the process so far. The goal is
to reach consensus, though consensus is sometimes not carefully
defined, and may never be achieved. In any case the technique improves
communication, reveals areas of agreement and disagreement, and
uncovers gaps in knowledge.

In Delphi, the selection of the "expert" panel is crucial and can skew
the results. The technique avoids the problems sometimes encountered
with dominant personalities in face-to-face discussions. To have a
chance of succeeding in reaching consensus on public policy issues,
Delphi would need to include experts that citizens trust.

To learn more, see Tickner 2001, Powell 2002, and Beech 1999.

3) Citizens Juries

Juries composed of citizens are a form of participation based on the
legal jury system and promoted by the Jefferson Center in Minneapolis,
Minnesota. The Center randomly selects a panel of 12 jurors who are
expected to represent the community. The jury is asked to study a
particular public issue (for example, solid waste, traffic congestion,
or physician assisted suicide); the jury meets for four or five days
to hear expert witnesses with a range of views on the issue,
deliberates, and then presents its recommendations to the public. The
Jefferson Center has trademarked the term Citizen Jury so if someone
wants to use this exact phrase they must go through the Jefferson
Center). On the other hand, anyone could create a similar process in
their own community and call it something like a "civic jury" without
violating copyright laws. This process may be limited because some
minority views may not be adequately represented, and there is no
guarantee that the results of the jury will become part of a decision.
Whoever sets up the jury process needs to make sure that these
problems are addressed. This description taken from Pellerano 2002.
See also Anonymous 2004 and Veasey 2004.

4) Consensus Conferences

Originally developed by the U.S. National Institutes of Health to
produce consensus statements on controversial medical topics,
consensus conferences are now being used by European governments to
reach consensus on controversial social issues (for example,
genetically altering livestock, telecommunications policy, or the use
of transplants in medicine). The conference is managed by a steering
committee that chooses a lay panel of 15 volunteer participants who
lack significant prior knowledge about the issue. Working with a
skilled facilitator, the lay panel discusses a government-provided
background paper on the subject and formulates questions for a public
forum. The government agency sponsoring the conference assembles an
expert panel including scientific, technical, social, and ethics
experts and stakeholders from unions, industry, and environmental
organizations. The lay panel then reviews more agency-provided
background papers, asks more questions, and suggests additions and
deletions to the expert panel. During the concluding four-day public
forum, the experts make presentations and answer questions from the
lay panel and sometimes from the audience. The lay panel deliberates
and then cross-examines the expert panel to fill in information gaps
and to clarify areas of disagreement. The lay panel then writes a
report, summarizing the issues on which it has achieved consensus and
identifying points of disagreement. Results of the panel are widely
distributed to the media and local hearings are held to stimulate
informed public debate, help citizens understand the issues, and
influence decision-makers. As with all these processes, serious effort
is needed to insure a diverse panel. This description was taken from
Pellerano 2002. See also work by Sklove here and here.

A Precautionary Approach

Given that numerical risk assessments have allowed the entire planet,
and all of its inhabitants, to become contaminated with toxic
chemicals, another approach seems in order. The precautionary
principle describes such an approach -- a constant search for the
least-harmful alternative, involving affected people in decisions, a
commitment to consider the consequences for the seventh generation, an
explicit, acknowledged duty to monitor outcomes and to take action to
prevent harm, with nature and human health being given the benefit of
the doubt. Risk assessment asks the question, "How much toxic exposure
can we get away with?" The precautionary approach asks, "How much
toxic exposure can we avoid?"

The precautionary approach suggests some large goals for us all to

** To make it repugnant and unthinkable to harm public health or
nature any more than is minimally necessary to achieve our human

** To make it repugnant and unthinkable to deprive anyone of liberty,
equality, or democracy any more than is minimally necessary to achieve
our human purposes. Achieving these goals will require deep cultural
shifts toward acknowledgment of limits and of the value of sharing.

My hypothesis about achieving such a deep cultural shift is that
adopting the precautionary principle at the local level will help
people adopt transformation goals.

Consider the San Francisco precautionary principle ordinance, which

"Every San Franciscan has an equal right to a healthy and safe
environment. This requires that our air, water, earth, and food be of
a sufficiently high standard that individuals and communities can live
healthy, fulfilling, and dignified lives.

"The duty to enhance, protect and preserve San Francisco's environment
rests on the shoulders of government, residents, citizen groups and
businesses alike." (The full text of the San Francisco ordinance is
available here.)

Notice that it starts with an assertion of rights and ends with an
assertion of responsibilities. And it suggests some worthy goals that
most of us can probably agree upon: everyone has a right to an
environment of sufficiently high quality to allow everyone to enjoy
healthy, fulfilling, and dignified lives.

Zero waste and the precautionary principle

Zero waste and the precautionary principle are two key ideas driving
a worldwide movement to reorder priorities, built on the bedrock of
the U.N. Universal Declaration of Human Rights of 1948. (Be sure to
see Paul Palmer's zero waste piece in this issue of Rachel's News.)

Some other parts of the same international movement can be described
by phrases such as clean production, extended producer responsibility,
the public trust doctrine, protecting the commons and our common
wealth, green chemistry, green engineering, green building,
biomimicry, cradle-to-cradle design, the soft energy path, sustainable
agriculture, global justice, and environmental justice.

Together, they aim to create the world anew with liberty, justice and
a peaceable, decent life for all. Another world really is possible.