13.2.1 Initial Evaluation (ERA Step 1)
The initial evaluation of need determines whether a risk assessment is required for a specific
case. Clearly defining the need as it meets the expectations of the final audience will help in
designing the overall risk assessment and determining how the information will be used and
communicated. Common reasons for conducting an ERA include regulatory requirements,
scientific inquiry, and scientific responses to public concerns.
13.2.2 Problem Formulation (ERA Step 2)
Once the need for the ERA has been clearly defined, the risk assessment moves forward to
the problem formulation phase. In this stage, appropriate risk hypotheses are defined in
order to address the scope of the assessment (e.g., whether Bt maize harms lovely nontarget
butterflies more than does conventional pest control). Biological aspects of the system, such
as the specificity of the mode-of-action and expression (of the particular genetic trait), the
spectrum of Bt activity, and Bt susceptibility of caterpillar, as well as relevant exposure pro-
files are considered while formulating the hypotheses. Other points to consider while iden-
tifying potential risks include the intended scale of cultivation (total USA or only a few
states) as well as other ecological considerations that might affect the environmental
impacts (e.g., protected areas with lovely butterflies near cultivation sites).
13.2.3. Controlled Experiments and Gathering of Information
(ERA Step 3)
The next step in the ERA involves conducting tests and experiments to gather data pertain-
ing to the study. For example, only a selected group of lovely butterflies can be feasibly
studied at one time under laboratory and later field conditions. Hence, species selection
must be done very carefully—ensuring that the butterfly species represent both ecologically
and economically important taxa.
13.2.4 Risk Evaluation (ERA Step 4)
The overall assessment of the risks is a complicated process. Evaluation of risk would
involve the consideration of several perspectives, and can easily go haywire. What is
known as thetiered risk assessmentmodel was introduced to enable a standardized scien-
tific evaluation of risks internationally. This method consists of several tiers, each consisting
of a description of the “problem” at a specific level and the approach to be followed in
dealing with it.
13.2.5 Progression through a Tiered Risk Assessment
Atiered risk assessmentis recognized as being the most appropriate and rigorous approach
to assess nontarget effects from both scientific and regulatory standpoints. Both hazards and
exposure can be evaluated within different levels or “tiers” that progress from worst-case
scenarios framed in highly controlled laboratory environments to more realistic conditions
in the field. Lower-tier tests serve to first identify and test potential hazards, and they are
conducted in the laboratory to provide high levels of replication and control, which increase
the statistical power to test hypotheses. Where no hazards are identified and the transgenic
crops are not different from conventional crops, the new product is regarded as “proven
13.2. ENVIRONMENTAL RISK ASSESSMENT (ERA) PROCESS 313