Risk assessment is a decision-making technique that first came
into use during the presidency of Jimmy Carter, who was trained
as a nuclear engineer. At its best, risk assessment is an honest
attempt to find a rational basis for decisions, by analyzing the
available scientific evidence. In theory it is still an
attractive ideal -- to make rational decisions based on
scientific evidence -- because in principle it should allow
diverse parties to agree on what needs to be done. However, 20
years of actual practice have badly tarnished the ideal of risk
assessment and have sullied the reputation of many a risk
History of Risk Assessment
During the late 1960s it slowly became clear that many modern
technologies had far surpassed human understanding, giving rise
to byproducts that were dangerous, long-lived, and completely
unanticipated. A book-length report issued by the White House in
1965 began with a letter signed by President Lyndon Johnson, who
said, "Ours is a nation of affluence. But the technology that has
permitted our affluence spews out vast quantities of wastes and
spent products that pollute our air, poison our waters, and even
impair our ability to feed ourselves." The 1965 White House
report identified numerous major sources of environmental
contamination: municipal and industrial sewage, animal wastes,
municipal solid wastes, mining wastes, and "unintentional
releases," which included automobile exhausts, smoke stack
emissions, pesticidal mists, and agricultural chemicals draining
into waterways, among others. The main report contained "subpanel
reports" on soil contamination, the potential for global warming
by carbon dioxide, the effects of chlorinating wastes, the health
effects of environmental pollution, and "the effects of
pollutants on organisms other than man."
In 1969, the U.S. Secretary of Health, Education and Welfare
issued another book-length report on "Pesticides and Their
Relationship to Environmental Health." The report said, "Recent
evidence indicates our need to be concerned about the
unintentional effects of pesticides on various life forms within
the environment and on human health. It is becoming increasingly
apparent that the benefits of using pesticides must be considered
in the context of the present and potential risks of pesticide
usage. Sound judgments must be made."
Therefore by the mid-1970s it was obvious even to journalists and
politicians that industrial technology had a massive dark side.
Technical mastery of natural forces was leading not to safety and
well being but to a careless and accelerating dispersal of
dangerous poisons into the biosphere with consequences impossible
During the 1970s, in response to a decade of disturbing reports
and revelations, a vast "environmental movement" developed, made
up of citizens concerned about one place or another -- their
dinner table, the playground in their neighborhood, the river
running through their town (often the source of their drinking
water). They demanded reforms. Congress reacted by writing laws
the size of a telephone book and by creating new agencies and
departments to issue enforceable regulations.
As all the early official reports make clear, in those days
environmental contamination was viewed through the twin lenses of
engineering and traditional toxicology. Traditional toxicology
maintains that "the dose makes the poison" -- meaning that
everything is poisonous at a high enough dose, and you can
prevent poisoning by giving a low enough dose. The engineer seeks
to develop a numerical formula that will give the desired result
time after time.
Blended together, these views gave rise to the idea that the
nation merely needed to set numerical "standards" for the
discharge of industrial poisons into the environment. The world's
capacity to absorb toxicants would be discovered by scientific
analysis, toxicologists would determine the safe dose, and
engineers would fine tune the nation's industrial apparatus to
deliver just that dose and no more. At least that was the theory.
Unfortunately, there was one key element missing from this
prescription: pollution pays handsomely. In the short run,
corporations that dump their toxic wastes into a river, or bury
them in the ground, make much more money than corporations that
sequester and detoxify their wastes at great expense. Therefore,
a political struggle of enormous proportions ensued. On one side,
the petrochemical giants (such as Dow, DuPont, and Monsanto) were
by then producing an array of profitable new products --
polymers, plastics, pesticides. On the other side, an alarmed
citizenry demanded safety. This got translated into "safe doses."
In response to the new laws and regulations, governments at all
levels geared up to make "sound judgments" inside this political
pressure cooker. Under these circumstances, "risk assessment"
seemed like a way to rationalize government decision-making,
instead of allowing bureaucrats to make arbitrary choices: gather
the necessary data, ask a group of impartial experts to interpret
it, and render a sound judgment. What could be more reasonable?
Unfortunately, it did not work out. In the first place, as we
shall see, the necessary data are not available, even today. In
the second place, the traditional toxicological assumptions did
not hold up under scrutiny. For many poisons, there is no safe
dose. And finally, impartial experts are almost never impartial.
Someone is paying their hefty fee and that someone often gets the
benefit of the doubt when it comes time to interpret whatever
data is available. Experts can be bought, it turns out.
In 1995, after risk assessment had been refined for 20 years,
three well-known and well-respected risk assessors working for
the California Department of Environmental Protection -- Anna
Fan, Robert Howd, and Brian Davis -- published a detailed summary
of the status of risk assessment. In it, they pointed out:
** There is no agreement on which tests to use to determine
whether someone's immune system has been damaged;
** There is no agreement on which tests should be used to assess
damage to the nervous system;
** There is no agreement on ways to test for genetic damage.
Without agreement on test methods, people cannot agree on which
data to include in a risk assessment. Under these circumstances,
different risk assessors will select the data that they believe
is relevant and they will usually reach different conclusions --
often VASTLY different conclusions.
Some kinds of toxicants present special problems because there is
no threshold for damage -- in other words, there is no dose below
which no effects occur. For these toxicants, any exposure may
cause some damage. For such toxicants, the only "safe" dose is
zero, if we define "safe" the way it is defined in a dictionary:
secure from threat or danger.
** Some genetic damage may be a nonthreshold event because
"direct chemical interactions with genes represent nonthreshold
phenomena," Fan, Howd and Davis say. [Thus, only zero is safe, if
safety is defined the way a dictionary defines it.--P.M.]
** If genetic damage occurs in a germ cell, it may be inherited
by successive generations. Thus, some genetic damage is
classified as damage to the reproductive system and/or the
developmental systems. These kinds of damage may have lifelong
effects: "a child may lead a less healthy life, may be more
susceptible to disease, or have shortened productivty and life
span," Fan, Howd, and Davis say. [For these kinds of damage, the
only safe exposure is zero.--P.M.]
** Cancer is a considered nonthreshold event under U.S.
regulatory law. Any exposure to certain carcinogens may initiate
a sequence that results in cancer. [Thus the only safe exposure
Fan, Howd, and Davis do not say so, but there are other problems
with risk assessments:
** Science has no way to analyze the effects of multiple
exposures, and almost all modern humans are routinely subjected
to multiple exposures: pesticides; automobile exhaust; dioxins in
meat, fish and dairy products; prescription drugs; tobacco smoke;
food additives; ultraviolet sunlight passing through the earth's
damaged ozone shield; and so on. Determining the cumulative
effect of these insults is a scientific impossibility, so most
risk assessors simply exclude these inconvenient realities. But
the resulting risk assessment is bogus.
** According to the U.S. National Academy of Sciences (NAS),
which in 1983 published the official formula for conducting a
risk assessment, risk assessments are supposed to take into
account the special characteristics of the population at risk:
Are they obese? Is their diet adequate? Do they suffer from
chronic disorders like asthma, diabetes, or arthritis? Are they
very young or very old? Are they pregnant? Do they eat unusual
quantities of contaminated foods, such as cheese or fish? Most
risk assessors simply ignore this NAS requirement for examining
the characteristics of a population.
** Risk assessment, it is now clear, promises what it cannot
deliver, and so is misleading at best and fraudulent at worst. It
pretends to provide a rational assessment of "risk" or "safety"
but it can do no such thing because the required data are simply
not available, nor are standardized methods of interpretation.
Science, as a way of knowing, has strict limits and risk
assessment encompasses a set of problems too complex for science
to solve. As Fan, Howd and Davis acknowledge, risk assessment is
not a science, it is an art, combining data gathered by
scientific methods with a large dose of judgment. Judgment is not
reproducible from laboratory to laboratory so different risk
assessors reach different conclusions, often based on who's
** Risk assessment is inherently an undemocratic process because
most people cannot understand the data, the calculations, or the
basis for the risk assessor's judgment.
Now after 20 years, the public is catching on, that risk
assessment has been a failure and in many cases a scam. Rather
than allowing citizens to reach agreement on what's best, it has
provided a patina of "scientific objectivity" that powerful
corporations have used to justify continued contamination of the
environment. With a few rare exceptions (sulfur dioxide
emissions, for example) dangerous discharges have increased
geometrically during the period when risk assessment has been the
dominant mode of decision-making. It is now obvious to most
people that risk assessment is a key part of the problem, not an
important part of any solution.
In place of risk assessment, a new paradigm is ripening: the
principle of precautionary action. The precautionary principle
acknowledges that we are ignorant about many important aspects of
the environment and human health. It acknowledges scientific
uncertainty and guides our actions in response to it. The
precautionary principle says,
"When an activity raises threats of harm to human health or the
environment, precautionary measures should be taken even if some
cause and effect relationships are not fully established
scientifically. In this context the proponent of an activity,
rather than the public, should bear the burden of proof. [See
"The process of applying the Precautionary Principle must be
open, informed and democratic and must include potentially
affected parties. It must also involve an examination of the full
range of alternatives, including no action."
The basic idea? Make decisions based on familiar maxims: An ounce
of prevention is worth a pound of cure. Look before you leap.
Better safe than sorry. Do unto others as you would have others
do unto you.
This is not rocket science. Definitely not rocket science.
--Peter Montague (National Writers Union, UAW Local 1981/AFL-CIO)
 John W. Tukey and others, RESTORING THE QUALITY OF OUR
ENVIRONMENT (Washington, D.C.: The White House, November 1965).
 Emil M. Mrak and others, REPORT OF THE SECRETARY'S
COMMISSION ON PESTICIDES AND THEIR RELATIONSHIP TO ENVIRONMENTAL
HEALTH, PARTS I AND II (Washington, D.C.: U.S. Department of
Health, Education, and Welfare, December 1969).
 A. Fan, R. Howd, and B. Davis, "Risk Assessment of
Environmental Chemicals," ANNUAL REVIEW OF PHARMACOLOGY AND
TOXICOLOGY Vol. 35 (1995), pgs. 341-368.
 National Academy of Sciences, RISK ASSESSMENT IN THE FEDERAL
GOVERNMENT: MANAGING THE PROCESS (Washington, D.C.: National
Academy Press, 1983).
Descriptor terms: history of risk assessment; precautionary