public panic may have stopped nuclear power for 50 years nuclear engineers emphasize safety...
TRANSCRIPT
Public Panic may have stopped nuclear power for 50 years
Nuclear Engineers emphasize safety improvements
Radiation experts and basic scientists are silent
Cost determined by virulent public opposition
These are the locations of measurement
British Journal of CancerVol. VIII, March 1954, No. 1
Sir Richard Doll & Peter Armitage(repeated 50 years later)
Cancer caused by a series of steps:
Effects of Low Doses Probability of Causation
and implications for Public Policy
The Future of Nuclear Power may depend upon a Rational Approach to
Risks of Radiation Exposure and their regulation.
What are they?Do we compensate those exposed?
If not what?
LINEARITY AT LOW DOSES
IS USUAL!!
Walking blindfold acrossHarvard Square is safe:
(Risk (R) = 0)IF THERE ARE NO CARS!
The risk (R) increases roughly in proportion
to the number of cars.
Acute Effects
Characteristics• One dose or dose accumulated in a
short time KILLS• 1/10 the dose repeated 10 times
DOES NOT KILL
CHRONIC EFFECTS including CANCER
Characteristics
A dose just sub-acute can give effects if repeated.
Usually not all people affected - dose response is flatter
Typically an accumulated Chronic Dose = Acute LD50
gives CANCER to 10% of the population.
E.g. LD50 for radiation is about 350 Rems.
At 350 Rems about 10% of exposed get cancer.
(more or less depending on rate of exposure)
Early Optimism Based on Poisons
There is a threshold below which nothing happens
__________J.G. Crowther 1924
Probability of Ionizing a CellLinear with Dose
Repair Mechanisms
BUTDoes the Mechanism Reject/Repair:ALL DAMAGED CELLS UP TO XXXX?
(implying a threshold)OR 99.999% of CELLS
INDEPENDENT OF DOSE
WE DON’T KNOW
CRITICAL ISSUES FOR LINEARITY
• The POLLUTANT actsin the same way as
whatever else influences the CANCER RATE
• CANCERS caused by the POLLUTANTare INDISTINGUISHABLE from other cancers
Probability of Causation
Come let us Cast Lots to find out who is to blame for this ordeal.
Jonah 1:7
Probability of Causation
equals
Risk from Substance
divided by
Risk from all Causes
Risk from all causes can be approximated as the Prevalence in a
similar Population.
If the cancer is rare, POC can be high even if the risk is low.
E.gPOC for berylliosis is unity for
beryllium as a cause
POC for asbestos exposure as a cause of mesothelioma among males is 80%
and 20% among females
Administrative Usesof the POC concept:
Aluminum workers in Quebec (compensate if POC > 50%)
Radiation Workers in UK (compensate if POC >20%)
Compensation for Radiation Exposures
1985 - Veteran “Downwinders”(if upper 99th percentile of POC > 50%;
effectively POC >5%)
1996 - UK Workers(if POC >20%)
2000 - Old AEC employees (if upper 99th percentile of POC > 50%;
effectively POC >5%)
Medical CausationGeneral Causation:
the Postulated Cause is Known to Cause the Disease under some conditions
(POC>0)
Specific Causation, exposure and other circumstances make POC large enough (>50%)
What do the Courts say?
US Supreme Court
DaubertJoiner
Kumho Tire
General Causation needs a Risk Ratio that is significant,
statistically and otherwise
Usually RR>2 (POC >50%)
Rule to avoid frivolous lawsuits:The postulated cause must be
“more likely than not” POC>50%
But Rutherford instruction
If total asbestos exposure is a proven cause, it can be assigned to individual
suppliers even if POC < 50%.
RISK of respiratory ailments
due to LIFETIME EXPOSURE toAIR POLLUTION is
3 to 5% average in the USA!
POC varies from 30% to 80%
If I develop leukemia:The POC from my Medical Exposures
would be over 50%
Can I sue using the Rutherford case?
Minister of Health, UKUS State Department
Harvard UniversityCommonwealth of Massachussets
ONRDOE (AEC)
Assignment of a Cause does not mean that Compensation is payable.
E.g.Chemotherapy agents are often
carcinogenic and increase risk of future cancers even as they cure.
Go back to the beginning: Does it make sense?
Can we study those cohorts where NIH calculate POC near 50%?
Risk Ratio of 2?
Those x-rayed just post world war II?