Human Health Risk Assessment Process

1. Human Health Risk Assessment Process Michael A. Jayjock, Ph.D CIH www.TheLifeLineGroup.org www.LINEAInc.com

2. Risk Assessment: Risk of What? • Being Poor? • Being Ugly? • Being Unhappy? • Having “Bad Hair”? • Being Sick? • Being Killed?

3. Risk of Adverse Human Health Effects ComingFrom “Agents”

4. RISK ASSESSMENT RISK= f (Bad Effects/Exposure)(Exposure)

5. Today we are going to look at: • Probability Statistics for Some Rare Events or Exposures (Putative vs Actuarial Risk) • Overview of Risk Assessment and Risk Management for Human Health • Basic Concepts of the Paradigm • Technical Models • Scientific Uncertainty as a Process Driver • Our Responsibility and Opportunities in all this as Professionals and Citizens.

6. Actuarial Risk and Putative Risk

7. Risk of Death Due to Injury, United States, for a person born in 2003 Re: http://www.nsc.org/lrs/statinfo/odds.htm

8. RISK IS UNAVOIDABLE IN OUR EVERYDAY LIVES Number of Deaths per Million Persons Annual Risk of Death in the US. Hazard All Causes 9,000.0 Motor Vehicle Accidents 210.0 Work Accidents 150.0 Homicides 93.0 Drowning37.0 Poisonings 17.0 Boating 0.6 Tornadoes 0.4 Bites and Stings 0.2 Source: Wilson, R. and Crouch, E., Risk/Benefit Analysis. Cambridge: Baltimore, 1982

9. RISK COMPARISONS FOR INVOLUNTARY RISKS Risk of Death / Person / Year Risk Influenza 1 in 5000 Leukemia 1 in 12,500 Struck by Automobile 1 in 20,000 Floods 1 in 455,000 Tornadoes (Midwest) 1 in 455,000 Earthquakes (California) 1 in 588,000 Nuclear Power Plant 1 in 10 million Meteorite ????? Source: Dinman, B.D., “The Reality and Acceptance of Risk,” Journal of the American Medical Association, Vol. 244 (11): 1126-1128, 1980.

10. “The Sky is Falling! The Sky is Falling!”Chicken Little (Early Risk Assessor)

11. Chicken Little was quite correctThe Sky IS FALLING:METEORS are Indeed Significant AGENTS of RISK forYou and I

14. DEATH BY METEORWhat is the risk?Morrison (NASA):We don’t know when the next NEO impact will take place, but we can calculate the odds. Statistically, the greatest danger is from an NEO with about 1 million megatons energy (roughly 2 km in diameter). On average, one of these collides with the Earth once or twice per million years, producing a global catastrophe that would kill a substantial (but unknown) fraction of the Earth’s human population.

15. There are 140 major craters on the face of the Earth, the vast majority of which are from 1-10 kilometer asteroids traveling at 11-74 km/s. Deadly, no? We expect three of these every million years, but there is, of course, no promise that a major NEO impact won't happen in our lifetime. Furthermore, a minor asteroid (50-100 meters wide) could cause large tsunamis about every century. Lastly, a 500 meter could devastate an area the size of Ontario and Quebec. Meteorites and Impacts Advisory Committee to the Canadian Space Agency http://miac.uqac.ca/MIAC/impactearth.htm

16. Tunguska (Siberia) Meteor Explosion June 30, 1908 at 7:17am • 60 meter (200ft) diameter Asteroid 30 degrees to the Horizon • 3-5 Megaton TNT Equivalent (~150 Hiroshima bombs -no radiation) • Detonated ~5 Miles Up • Hundreds of Square Miles of Devastation. • Herds of Incinerated Reindeer • Unknown number of persons killed

18. Apophis is Coming 2029 and 2036

20. A Less Dramatic and More Detailed Discussion On-Line http://www.space.com/news/051103_asteroid_apophis.html • It’s 1000 ft in Diameter (5x Tunguska) • Will just miss Earth in 2029 • But could be perturbed enough to hit earth on it’s return pass on Friday, April 13, 2036

21. It is almost impossible to Effectively Manage Any Risk which has not been Reasonably Assessed. Rule #1:

22. DEATH BY METEOR (CONTINUED)What is the risk?Reduced to personal terms, this means that you have about one chance in 20,000 of dying as a result of a collision. Such statistics are interesting, but they don’t tell you, of course, when the next catastrophic impact will take place - next year or a million years from now (emphasis added).David Morrison,Responsible NASA Officialdmorrison@mail.arc.nasa.gov

23. CONCEPTOF DE MINIMIS RISK • De minimis risks are those risks judged to be too small to be of social concern, or too small to justify the use of risk management resources for control. • The De minimis risk level frequently used by government agencies (EPA, FDA) is 1 in 1,000,000 or “1 in a million” increased risk of an adverse effect occurring over a 70 year lifetime in a large population.

24. “There is no point in getting into a panic about the risks of life until you have compared the risks which worry you with those that don’t, but perhaps should.” (Lord Rothschild, The Wall Street Journal, 1979). The 1 in a million risk level used to regulate some chemicals and other hazards is many times below risks which people face every day.

25. RISKS THAT INCREASE PROBABILITYOF DEATH BY ONE IN A MILLION Cause of Death Activity Smoking 1.4 Cigarettes Cancer, Heart Disease Traveling 10 miles by Bicycle Accident Traveling 300 miles by Car Accident Flying 1000 miles by JetAccident One Chest X-Ray Cancer from Radiation Source: Wilson, R., “Analyzing the Risks of Daily Life,” Technology Review, 81, (1979).

26. Actuarial Risk of the Space Shuttle • 1981 – predicted to be 1 in 78 • 1986 – Challenger lost on the 25th flight 1 in 25 • 1986+ NASA set goal 1 in 1000 • Later 40% budget cuts caused the predicted/goal risk to slip to 1 in 250 • 2003 – Columbia lost on 113th flight: 1 in 56.5 Ref: Discovery, v25, n1, p.30

27. Our Lifetime Risk of Dying in an Automobile Accident is 1 in 90!!!

29. Overview of Risk Assessment and Risk Management

30. Principal Elements of Risk Assessment • Anticipation • Recognition • Evaluation Effect/Dose = Dose-Response Dose = Exposure Control is NOT an element

31. Anticipation, Recognition and Evaluation are Risk AssessmentControl is Risk Management

32. Rule #1 (again): It is highly problematic to rationally MANAGE any risk which has not been reasonably assessed. or “Doing Risk Management without Risk Assessment (i.e., DATA) is Tough”

33. Risk is an EQUAL Functionof Toxicity and Exposure • Risk = Toxicity X Dose • Exposure Dose • Risk Toxicity X Dose Paracelsus Understood Risk Assessment

34. Operationally: Dose = Exposure Toxicity and Exposure are Equal Partners in Risk Assessment

35. Rule #2: The Precautionary Principle • Axiom of Conservatism • Err on the Side of Safety • Trade Conservatism for DATA

36. TOXICOLOGY:THE FIRST HALF OF HUMAN HEALTH RISK ASSESSMENT

37. Putative versus Actuarial Risk • The Estimated Quantitative Risk at the Low Dose of an OEL are essentially PUTATIVE (i.e., ascribed based on testable but untested assumptions). • High Consequence - Low Probability (e.g., lotteries, accidents) events occur with historically validated consistency - ACTUARIAL.

38. Dose Typical rodent data Response

39. Dose How do you get there from here? Response ?

40. Dose How do you get there from here? Response

41. Dose How do you get there from here? Response

42. Dose How do you get there from here? Response

43. Dose How do you get there from here? Response

44. The only time a quantitative level of risk is estimated at an exposure limit is in the case of cancer risk. (10-5 or 10-6 for non-workers, ca. 10-3 for workers).It is assumed that there is an acceptably “low” but essentially indeterminate level of adverse risk for other health effects at the exposure limits.

45. Cancer Risk x -0 10 X x X LINEARIZED DOSE-RESPONSE MODEL -1 10 x X -2 10 x = DATA -3 10 Predicted Incidence of Liver Tumors -4 10 -5 10 -6 10 1e-6 1e-5 1e-4 1e-3 1e-2 1e-1 1e+0 1e+1 1e+2 Dose in mg/kg

46. DRAW and Discuss Various DR Possibilities HERE

49. Quantitative Level of Protection Offered to Workers by ACGIH Threshold Limit ValuesOccupational Exposure Limits AIHAJ (62) January/February 2001 M.A. Jayjock1; P.G. Lewis2; J.R. Lynch3 1Rohm and Haas Co., Spring House, PA; 2Rohm and Haas Co., Bristol, PA; 325 Waterman Ave., Rumson, NJ 07760

50. Practical Risk Evaluation versus Pure Risk Assessment • Practical Risk Evaluation as Practiced Today – is Not Elegant Science • Uses Best Estimates and Subjective Judgment • Relatively Inexpensive but (if done correctly) a Somewhat Crude OVERESTIMATION of Risk • Fraught with Uncertainty and Controversy