• Decrease font size
  • Return font size to normal
  • Increase font size
U.S. Department of Health and Human Services

Animal & Veterinary

  • Print
  • Share
  • E-mail

Setting a Risk Threshold for Carcinogens Lifetime Risk

SLIDE 1: What is Origin of 10^-6?

Curtis Travis
Quest Technologies

SLIDE 2: What Is Origin of 10^-6?

Two approaches to regulating carcinogens

  • FDA- Level of risk equivalent to zero
  • EPA- Level of risk below regulatory concern

 

SLIDE 3: What Is Origin of 10^-6?

  • Kathryn Kelly 1991 paper
  • No documented origin of 10^-6
  • Adopted by FDA as “essentially zero”
  • Not intended as definition “acceptable risk”
  • EPA doesn't use as definition of acceptable risk

 

SLIDE 4: What Is Origin of 10^-6?

FDA Origin

  • 1958 Delaney Clause
  • Level of risk equivalent to zero
  • Mantel-Bryan 1961 paper 10^-7 to 10^-8
  • 1973 Federal Register 10^-8
  • 1977 Final rule 10^-6

 

SLIDE 5: What Is Origin of 10^-6?

EPA Origin

  • Roy Albert 1994 paper
  • Level of risk below regulatory concern
  • EPA water office--in hallway conversation
  • Recommendation was 10^-5 to 10^-7
  • Easy jump to 10^-6
  • Small chance -- “a girl in a million”

 

SLIDE 6: Examples of Existing Standards

  • FDA- essentially zero risk- 10^-6
  • Safe Drinking Water Act target level- 10^-6
  • Superfund- 10^-4 to 10^-6
  • State RBCA soil and water- 10^-4 to 10^-5
  • Review of 132 regulatory decisions- 10^-4
  • Clean Air Act- 10^-4
  • Radon regulation- 2.8x10^-2

 

SLIDE 7: Commonplace Risks Are High

  Lifetime Risk
All cancers 2.0x10^-1
Motor vehicle 1.7x10^-1
Home accidents 8.0x10^-3
Electrocution 3.7x10^-4

 

SLIDE 8: Background Cancer Risk from Global Pollutants

  • Examples:
    • Benzene, Trichloroethylene in air
    • Chlorform in water
    • Dioxin, PCBs in food
  • Total Background Cancer Risk 1.4x10^-3

 

SLIDE 9: EPA Acceptable Level of Risk

  • Target Risk Range 10^-4 to 10^-6
  • de minimis level 10^-6

 

SLIDE 10: Summary of Acceptable Risk Level

  • Regulatory Guidance from 10^-6 to 10^-4
  • Normal Everyday Risk from 10^-2 to 10^-1
  • Background Chemical and Radiation Risks from 10^-3 to 10^-2
  • Acceptable Level of Risk is Socially Determined