Risk Management: A Conceptual Introduction

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Risk Management A Conceptual Introduction

• Tee L. Guidotti
• Occupational Health Program
• University of Alberta

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Dimensions of Risk Management

• Risk perception
• Risk communication
• Risk control
• structural change
• reduce exposure
• reduce potential loss or liability
• Risk anticipation
• Risk comparison

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What is Risk - Really?

• A conceptual abstraction - risk does not exist
  per se
• Risk is a description of the behaviour of a
  system, either in past or predicted
• Risk reflects characteristics of the system,
  subject to change
• Risk is fundamental to change or adaptation
• All society is about mitigating risk

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Levels of Risk

• 0.5
• 0.05 (p value)
• 0.01 - 0.1
• 10-5 - 10-4
• 10-5

• Legal standard of certainty
• Allowable scientific error
• Clinical complications
• Public health
• (e.g. vaccine safety)
• De minimis

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Risk Perception
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Risk Perception

• Public view of risk may not match that of experts
• People tend to estimate risk best in the middle
  of the range - they distort the extremes
• Risk perception is laden with values learned in
  society and the family
• Risk perception is culturally determined
• Risk is perceived as good in many contexts

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Risk Communication
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Cardinal Rules for Risk Communication

• Accept, involve public as legitimate partner
• Plan carefully and evaluate performance
• Listen to the audience
• Be honest, frank and open
• Coordinate, collaborate with other credible
  sources
• Meet the needs of the media
• Speak clearly and with compassion
• After Covello originally prepared for U.S. EPA.

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Risk control

• structural change
• engineering and environmental change
• replacement
• reduce exposure
• protection
• isolation
• reduce potential loss (mitigate effects)
• reduce potential liability

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Achieving Risk Control

• Market incentives
• Regulation
• Voluntary compliance
• may involve mutual coercion
• role of guidelines
• indirect regulation
• Cultural norms

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Risk Control through Regulation
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Regulatory Options
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Standards v. Guidelines

• Standards
• Legal authority usually delegated
• Binding
• Mandatory compliance
• Enforceable
• Universal application
• Consultation process

• Guidelines
• Authority usually negotiated
• Advisory
• Voluntary compliance
• No sanctions
• Discretionary
• Multistakeholder process

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Examples of Standards - US
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Examples of Guidelines - US
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Standards and Guidelines in Canada
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Establishing Exposure Standards

• Occupational v. environmental (assumptions of
  vulnerability)
• General benchmark required
• risk based
• non-degradation (historical)
• reference level, ? NOAEL/safety factor
• technology-driven
• Appropriate model for extrapolation

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How Standards Are Set - U.S. EPA as an Example
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Two Models for Standard Setting

• Noncarcinogens (direct effects model)
• Carcinogens (stochastic model)
• These standards-setting models flow logically
  from the risk assessment models used for each.

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Model Non-Carcinogens

• Standards for non-carcinogens typically assume a
  toxicologic exposure-response relationship
• based on known exposure-response slope
• identify NOAEL, extrapolate to humans
• safety factors (uncertainty factors)
• Acceptable risk is below chronic toxicity level
  for most vulnerable subgroups

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RfD NOAEL/(UF1 ? Ufn)
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Safety Factors (US EPA)
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Model for Carcinogens

• Stochastic model, derive maximum likelihood
  estimate or UCL of frequency-response slope
• Derive unit cancer risk, q1
• Individual lifetime cancer risk
• exposure ? slope
• Adjust allowable exposure to de minimis risk
  level (? 105)

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Implications of Model for Carcinogens

• Because risk level is preset, little flexibility
• Safety factors do not apply
• Low-dose extrapolation on-going debate
• Tends to drive standards-setting in mixtures of
  carcinogenic, non-carcinogenic agents
• benzene in Cdn drinking water guidelines
• benzene drives BTEX-based evaluations
• PAHs drive CCME guidelines

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Historical Derivation of Standards

• Consensual process or majority of an
  authoritative group
• Based on review of the evidence
• Considerable debate in camera
• Issues of role and conflict of interest
• Problem of disinterested expert
• Disillusionment and opening of process

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Risk Anticipation

• New idea, in evolution
• Anticipate risk before it becomes a management
  problem
• Requires internal culture of skepticism

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Risk Comparison

• A systematic process of consultation in an open,
  multistakeholder process
• expert panels
• public(s)
• Iterative process in open discussion
• Consensus on magnitude of risks
• Consensus on priorities and ranking of risks

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Risk Comparison

• Benefits
• Consensus, once achieved, is solid
• Broadly inclusive
• Educates constituencies
• Direct guidance for public priorities, e.g.
  budgets
• Provides framework for NGO participation

• Drawbacks
• Very time consuming
• Easily hijacked
• Requires active outreach to constituencies
• NGOs may lead public
• NGOs may not be representative of public opinion