1. The Development of Risk Analysis: A Personal Perspective March 19 th 2012 2:30pm Harvard School of Public Health Richard Wilson Mallinkrodt Professor of Physics (emeritus)

3. 1800s– Try out the technology, modify if any problems arise. In 1833, when the first passenger railway in the world Liverpool to Manchester opened, an engine ran down a Member of Parliament, who failed to get out of the way. Was the outcome good or bad? Depends on his Party affiliation!

4. What do we mean by Risk? Measures of Risk How do we Calculate Risk? (a)History (b) Event Tree (c) Animal Analogy (d) Other

8. What about public perception?

10. Yet data show unequivocally that life is getting better. We all know that! So what are the public saying?

11. What is Life Expectancy? Both the specific death rate and the life expectancy at birth have a dip at 1919 world wide influenza epidemic. BUT anyone born in 1919 will not actually see this dip. Peculiarity of definition of life expectancy.

12. Uncertainties and Perception Types of Uncertainties Role of Perception Kahneman ’ s 2002 economics Nobel prize (Tversky and Kahneman, 1981) People are inconsistent but the inconsistency has a pattern Major differences between Public and Expert perceptions

13. Tversky’s Analysis Assuming that the U.S. is preparing for an outbreak of a disease imported from Asia two alternative programs: Program A: 200 people would be saved. Program B: 1/3 chance that 600 will be saved and 2/3 that no one will be saved. (72%)

14. Alternatively… Program C: 400 people will die. Program D: a 1/3 probability that no one will die and a 2/3 probability that 600 will die. Tversky’s Analysis (cont.) (78%)

15. Simple arithmetic tells us that options C and D have the same effect as options A and B. When the question was posed as saving lives the students were risk averse. BUT When the question was posed as preventing deaths they favored risk! Stanford and Harvard students were the same

16. MEASURES of Risk Simple risk of Death (assuming no other causes) by age by cause Risk of Injury by cause by type by severity Per year lifetime unit operation event ton unit output

17. RISK MEASURES (continued) Loss of Life Expectancy (LOLE) Years of Life Lost (YOLL) Man Days Lost (MDL) Working Days Lost (WDL) Public Days Lost (PDL) Quality Adjusted Life Years (QALY) Disability Adjusted Life Years (DALY) Different decisions may demand different measures

18. LOLE from cigarette smoking In USA 600 billion cigarettes made (presumably smoked) 400,000 people have premature death (lung cancer, other cancers, heart) 1,500,000 cigarettes per death Each death - 17 years (8,935,200 minutes) off life or 6 minutes per cigarette ABOUT THE TIME IT TAKES TO SMOKE ONE

19. What questions are you asking? IF YOU DON’T KNOW… THE CHANCE OF A SENSIBLE ANSWER IS REDUCED.

20. The Importance of Models Every risk calculation involves a model. The simplest is: NEXT YEAR WILL BE LIKE LAST YEAR. NEXT YEAR WILL BE LIKE LAST YEAR WITH IMPROVEMENTS. EVERY MODEL HAS ASSUMPTION WHICH MUST BE CLEARLY STATED

21. Wigner: “whenever there is a lot of energy in one place and a lot of people in the same place, there is a potential for disaster. 1848– no petroleum products brought up the Thames River closer than 30 miles east of London Bridge (Canvey Island) (VERY WISE) 1978– 120 seventeen million gallon tanks in Canvey (for LNG each is 20 Hiroshimas) Plus 500 vacation cottages With one access road EASY TO IMAGINE DISASTER

22. Even ignored historical data includes big risks 65 million years ago - large meteor impact may have destroyed the dinosaur Risk per year 1/65 million for everyone Lifetime risk 1 in a million including smaller impacts we get lifetime risk 1/100,000 Yet EPA pretended to regulate at 1 in a million!

23. Beware of risk assessments that make assumptions that an important parameter is precise. (US EPA)

24. Large Accidents in New Technologies After World War II, the old paradigm was inadequate: “try it and if it gives trouble, fix it” Society now demands evidence, in advance, that the technology is safe. The first major example was nuclear energy. WHY WAS THAT THE FIRST EXAMPLE?

25. A number of reasons have been suggested: 1)The new technology was in hands of fundamental scientists from start: 1946 The US Atomic Energy Commission (AEC) 2)The new technology used new physical principles. 3)The new technology arose simultaneously with a new deadly form of war. 4)The new technology posed unprecedented hazards.

26. Atomic Energy Commission Established an Advisory Committee on Reactor Safeguards (ACRS) to advise on safety. Outstanding Scientists: Glenn Seaborg, John Von Neuman, Robert Bacher, Edward Teller, Eugene Wigner and Richard Feynman

27. Defense in Depth (a name borrowed from the military) Imagine the worst thing that can reasonably go wrong in the reactor, the “Maximum Credible Accident” devise an engineered safeguard to prevent it Large reactors, particularly first in a series, in unpopulated areas, following Wigner’s principle. The Reactor Safety Study (Rasmussen et al. 1975) calculated beyond the maximum credible accident

29. ASSUMPTIONS (1)We have drawn all possible trees with consequences (2)The probabilities are independent (design to make them so; look very carefully at correlation (3)Consider carefully - with some confidentiality - actions that can artificially correlate the separate probabilities

30. INDEPENDENCE IS CRUCIAL DO NOT break down detail in event tree beyond what independence allows Fukushima: Earthquake and Tsunami are NOT independent But effect of radiation and accident calculation are independent

31. BUT! A TERRORIST GROUP CAN DESTROY INDEPENDENCE: INITIATE A PIPE BREAK (SMALL BOMB) AND BOMB ON CONTAINMENT AT THE SAME TIME SET OFF WHEN WIND IS BLOWING TOWARD CITY

34. What about chemicals Paracelsus - “The dose makes the poison” More is worse Less is better IS there a threshold? BUT beware of exceptions

35. Epidemiology Associate Death (or other Measure) to Postulated Cause Is it statistically significant? Are there alternative causes (confounders)? No cause is generally accepted unless there is a group where death rate has doubled. Risk Ratio (RR) > 2 But beware of stupid answers

37. Obviously storks bring babies. BUT direction of causality may be wrong Babies bring storks Correlation, by itself, does not imply causality Yet in March 2012 : NH legislature correlation between women’s cancer rate and prostate cancer implies causality

38. Issues in Low Dose Linearity Is the observed effect identical to one that occurs naturally? – (pathologists should not be able to tell difference) Is DNA the same? – IF so: consider natural processes at same time as pollutant Probable that somewhere in the cancer causing mechanism a pollutant acts like a natural process and a bit more cancer (linear) (radiation cancers, chemical cancers, lung from air pollution) – But slope extrapolated down from high levels

39. Issues in Low Dose Linearity Implicit in Armitage and Doll (1954) Explicit in Crump et al. (1976) extended to any outcome including air pollution Crawford and Wilson (1996)

41. We contrast two types of medical response to pollutants. ACUTE TOXIC EFECT A dose within a day causes death within a few days (causality easy to establish) CHRONIC EFFECT lower doses repeated give chronic effects (cancer, heart) within a lifetime. (Causality hard to establish)

42. Characteristics One dose or dose accumulated in a short time KILLS 1/10 the dose repeated 10 times DOES NOT KILL

43. Early Optimism Based on Poisons There is a threshold below which nothing happens BUT J.G. Crowther 1924 Probability of Ionizing a Cell by radiation is Linear with Dose Naively this would lead to many cancers each second. There must be a repair mechanism. Is that linear?

44. Incremental Risk can actually be greater than the simple linearity assumption of a non-linear biological dose-response is assumed ALSO Possible to have 2 effects. One benign or beneficial, other adverse

45. Can animals help us? Especially laboratory animals, rats and mice Rat lung and human lung are similar

49. These principles do not work for cancer Arguments due to Richard Peto Rat lungs look like people’s lungs If a piece of tissue is equally likely to develop a cancer whether attached to rat or man Cancer in man/cancer in rat (for same dose) =( ) x (mass-man/mass-rat) =millions Actually closer to one Test needed. Compare rats and mice use whatever human data we have (20 or so chemicals)

50. Usual model: A toxic chemical will be carcinogenic highly toxic - highly carcinogenic If carcinogenic in animals carcinogenic in people. What is the uncertainty in this assumption? What do data say? What does EPA say?

51. Different End Points Behave Differently Alcohol in moderation reduces the incidence of stroke Alcohol is an animal carcinogen and in conjunction with cigarettes increase lip cancer drastically Alcohol is a narcotic and in large quantities has dramatic side effects (auto accidents etc)

53. – Minimum is uncertain. – Sir Richard Doll orally said he thought it is too low. – What does that tell you?

54. What is the Precautionary Principle? Do not do anything unless you personally understand the effects Do not do anything unless all politicians agree on the effects Do not do anything unless a “responsible committee” understands the effects Do not do anything unless there is scientific agreement. Do not do anything unless one person says the effects are small

55. ARSENIC A DISASTROUS EXCEPTION Animals did not get cancer from arsenic ( till Jack Ng in Bribane fed them an organic compound ) Why should people get cancer? The world was not looking

56. 1880 Hutchinson cancers from long use of Fowler’s solution 1930 Angiosarcoma in farmers (NOT DUE TO VINYL CHLORIDE) 1965 skin cancers in Taiwan threshold suggested 1976 data from Taiwan ignored for many years Risk at present EPA regulatory level 100 times level of anything else EPA regulate Many millions exposed in SE Asia What is the next disaster we are missing?

57. What about Fibers? (Asbestos) Pliny - Asbestos means does not burn ( That is why we liked it before 1970 ) 1970 Asbestos means one of 6 materials in commerce Bulk mineral not measurably carcinogenic cleavage fragments probably weakly carcinogenic fibers very carcinogenic A PHYSICAL CARCINOGEN NOT A CHEMICAL ONE Animal data not helpful Are all 6 the same? No.

58. No alternative to EPIDMIOLOGY 2 groups distinguishable by electron microscope Amphiboles - Serpentine (Chrysotile) Chrysotile does not stay long in lung Crocidolite stays 40+ years This explains why crocidolite causes mesothelioma (latent period 40 years) and Chysoltile at least 200 times less. 1986 Few Electron microscopes available: EPA assumed all 6 the same; regulated fiber counts only 2006 EPA realizes that there are differences. Maybe in 2012 the lawyers will understand.

59. In Order of Nastiness: Crocidolite Amosite Tremolite? Chrysotile lung cancer with 20 year latency mesothelioma 40+ years latency

60. Is Carbon Burning Causing Climate Change? Standard model 1750 Sun heats earth and earth reradiates – Then temperature -70 degrees Celsius (200K) 1827 Fourier suggested we are in a greenhouse 1870 Tyndall measured CO 2 and H 2 O infrared spectra – CO2 uniform in atmosphere H2O non uniform 1897 Arrhenius calculated effect of ice ages 1945 Dobson pointed out deep and surface oceans do not mix 1960 + Keeling measured CO 2 at Muona Loa, Hawaii – In detail still very uncertain

61. Each Step Needs Verification Sun’s radiation – sunspot cycle now suggests less radiation than usual Do carbon emissions stay in air? (50%) – Ocean-air interaction crucial – (different in Atlantic and Pacific) Is upper atmosphere disconnected from lower atmosphere? THESE QUESTIONS ASSUMED POLITICALLY IN 1981 – Models never run with all uncertainties Reopened in 2000 by – aggressively of some scientists – bad bill in Congress (Waxman-Markey) – (pork barrel with a thin veneer of climate change)

63. Difficult though it is to get scientific agreement Hard though it is to get a detailed risk assessment from EPA that I like It is harder to get the main body politic to face the truth

64. Why Invade Iraq? Iraq is close to having nuclear weapons? – Few at Los Alamos believed that they were They have a lot of chemicals/nerve gases? Less < 1/1000 of US storage in Umatilla, Oregon Bush Jr. did not like Saddam? (Saddam tried to kill his father) The next slide gives the answer.

65. It is the Oil, Stupid

66. Topical issue – Fukushima a year ago- Evacuate or not? What do we know from previous incidents? Those who do not understand history are condemned to repeat it Medical X rays Radium Dial painters Hiroshima-Nagasaki Windscale (UK) TMI Chernobyl Tokai (Japan)

67. Avoid Acute Radiation Sickness (ARS) ARS can occur if dose in a week is > 200 Rems (2 Sv). But chronic doses can accumulate over years Chronic effects: cancer heart disease genetic effects No cancers specific to radiation Radiation can cause an increase in natural cancer rate Perhaps 30% at 200 Rems (maybe much less)

68. My Estimate of Dose at Site Boundary

69. My Dose at Site Boundary March 2012 calculation – Peak probably noble gases (little effect) followed by cesium. (134 and 137) – Take peak and multiply by width – Dose about 2 Rems (0.02 Sv) and falling – My CAT scan doses last year 2.4 Rems

70. What about Ibaraki? (on way to Tokyo)

71. It looks different with different scale. Dose Negligible

72. Adverse Effects of Evacuation – Stress can increase cancer rates 5% or more – Direct loss of life due to lack of facilities – NO ONE CONSIDERED THESE AT ALL

73. Subsequent study (IAEA, INPO, TEPCO, etc) says: No one got Acute Radiation Exposure (highest exposure in a worker 30 Rems) If there are cancers the probability will be less than 50% in all but a few cases.

74. These are the locations of measurement

76. BEIR report on effects of radiation

77. Deposition to NW of plant highest from Tuesday/Wednesday releases

79. Comparison with other disasters

80. What should a decision maker have done (my personal opinion)? Order an immediate evacuation for many km ? NO Make it easy for any VOLUNTARY evacuation – (to avoid panic as happened after Katrina (YES) Do simple steps to reduce exposure to fall out – including measurement (YES) ORDER all out clean up for years (NO) facilitate individual towns and people in voluntary steps (YES) Richard Wilson paper in DOSE_RESPONSE (2012) (circulated)

81. Should US troops stay in Afghanistan? They seem to cause trouble. If an Afghan is angry what are his alternative courses of action?