Risk Management: A Conceptual Introduction Tee L. Guidotti Occupational Health Program University of Alberta.

Risk Management: Risk Management: A Conceptual A Conceptual IntroductionIntroduction

Tee L. Guidotti

Occupational Health Program

University of Alberta

Dimensions of Risk Management

• Risk perception

• Risk communication

• Risk control– structural change– reduce exposure– reduce potential loss or liability

• Risk anticipation

• Risk comparison

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

Levels of Risk

Legal standard of certainty

Allowable scientific error

Clinical complications

Public health

(e.g. vaccine safety)

De minimis

0.5

0.05 (p value)

0.01 - 0.1

10-5 - 10-4

10-5

Risk Perception

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

Risk Communication

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 compassionAfter Covello; originally prepared for U.S. EPA.

Risk control

• structural change– engineering and environmental change– replacement

• reduce exposure– protection– isolation

• reduce potential loss (mitigate effects)• reduce potential liability

Achieving Risk Control

• Market incentives

• Regulation

• Voluntary compliance– may involve mutual coercion– role of guidelines– indirect regulation

• Cultural norms

Risk Control through Regulation

Regulatory Options

Market, informedchoice

Tobacco products

Ban/Prohibition Conspicuous hazardCost/Benefit Consumer product safetyRisk/Benefit Occupational standardsRisk/Risk Drug regulationTechnology-driven Air emissions, BACTAcceptable risk Environmental standards

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

Examples of Standards - US

PEL OSHA TWA, STEL

NAAQS EPA Air quality

Emissions regs State, regionalAQMDs

Site-specific,subject to trading

Water qualitystandards

EPA Bodies of water

Discharge limits State, localauthorities

Site-specific

Consumer products CPSC, FDA, FSQS Quality and safety

Radiationprotectionstandards

NRL Based on cum dose

Examples of Guidelines - US

REL NIOSH Recommended toOSHA

TLV ACGIH Recommended,private status

Standards and Guidelines in Canada

OEL, specificstandards

Occupationalhealth

Standards

Air quality guidelines Federal-provincial

Guidelines(formerlyobjectives)

Cdn Drinking WaterGuidlines

Federal-provincial

Guidelines

Emissions, effluentstandards

Provincial Standards

Remediation CCME Guidelines

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

How Standards Are Set - U.S. EPA as an Example

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.

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

RfD = NOAEL/(UF1 … Ufn)

NOAEL,NOEL

No observed (adverse) effectlevel

LOAEL,LOEL

Lowest observed (adverse)effect level

RfD,RfC

Reference dose or concentration(for airborne exposures)

UF,MF

Uncertainty factor, “modifying”factor, (safety factor)

Safety Factors (US EPA)

UF1 Intraspecies variation 1 – 10

UF2 Potential + -interaction 1 – 10

UF3 Route of exposure adjustment 1 – 10

UF4 Fraction of intake attributableto source

Variable

UF5 F = 1 for NOAEL,F = 10 for LOAEL

1 or 10

UF6 Interspecies extrapolation,F = 1 for humanF = 10 for animal data

1 or 10

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 ( 10–5)

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

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

Risk Anticipation

• New idea, in evolution

• Anticipate risk before it becomes a management problem

• Requires internal culture of skepticism

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

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