04/11/23 Illinois Department of Nuclear Safety 1

Health Effects Of Health Effects Of RadonRadon

And Its Decay ProductsAnd Its Decay Products

04/11/23 Illinois Department of Nuclear Safety 2

Radon Is a Class A Known

Human Carcinogen

Alpha particles from the radon decay products

can damage lung tissue.

Lung cancer is the main health effect.

04/11/23 Illinois Department of Nuclear Safety 3

History An “unknown” lung disease in miners in the 1400’s. Identified in 1879 in autopsies of European miners

as lung cancer (Lymphosarcoma). Excess lung cancer deaths observed in uranium

miners in U.S., Czechoslovakia, France and Canada. Excess lung cancer deaths in other underground

miners in Newfoundland, Sweden, Britain, France, Australia, China, and U.S.

04/11/23 Illinois Department of Nuclear Safety 4

Mechanism of Lung Cancer Induction

Radon and RDPs breathed in. Radon exhaled. RDPs remain stuck to lung tissue. Po-218 and Po-214 emit alpha

particles. Alpha particles strike lung cells

causing physical and/or chemical damage to DNA.

04/11/23 Illinois Department of Nuclear Safety 5

How RDPs Impact Lung Tissue

RDPs stick to lung.RDPs stick to lung. Alpha energy Alpha energy

delivered directly to delivered directly to cells.cells.

LungLung

Bronchial TubesBronchial Tubes

Particle with Attached Radon Decay ProductsParticle with Attached Radon Decay Products

RespiratoryRespiratoryTractTract

AlveoliAlveoli

BronchiolesBronchioles

Mucous LayerMucous LayerCiliaCilia

Alpha ParticleAlpha ParticleEnergy DepositedEnergy Depositedin Live Cells inin Live Cells inthe Bronchialthe BronchialEpitheliumEpitheliumConnective TissueConnective Tissue

BronchialBronchialEpitheliumEpithelium

Air SpaceAir Space(Bronchial Tube)(Bronchial Tube)

04/11/23 Illinois Department of Nuclear Safety 6

Physical and Chemical Damage to DNA from Radiation

Physical damage Physical damage occurs when DNA occurs when DNA struck directly.struck directly.

Chemical attack can Chemical attack can occur from ions and occur from ions and free radicals created free radicals created when radiation impacts when radiation impacts fluid surrounding fluid surrounding DNA.DNA.

OH OH --

H H ++

HH22OO

04/11/23 Illinois Department of Nuclear Safety 7

Scientific Basis for RadonRisk Estimates

Studies on miners.

Committee on the biological effects of ionizing

radiation (BEIR).

– National Academy of Sciences, and NRC

Studies on residential occupants.

Laboratory animal studies.

04/11/23 Illinois Department of Nuclear Safety 8

EPA Risk Assessment (1992)

Radon-Related Lung Cancer Risk:

– Lifetime Risk at 4 pCi/L Action Level:

1:100 (10-2) for Smokers

1:1000 (10-3) for Non-Smokers

– Central risk estimate:

14,000 lung cancer deaths/year

Uncertainty Range: 7,000 to 30,000 deaths/year

04/11/23 Illinois Department of Nuclear Safety 9

Residential Risk Affirmed by: The National Academy of Sciences (NAS) The International Commission on Radiological Protection

Committee (ICRP50) The National Council on Radiation Protection and Measurement The World Health Organization's International Agency for

Research on Cancer (IARC) and Working Group on Indoor Air Quality: A Risk-Based Approach to Health Criteria for Radon Indoors

The NCI-led International Reassessment of Radon Miner Data

04/11/23 Illinois Department of Nuclear Safety 10

IDNS STATE POLICY IDNS STATE POLICY RECOMMENDS THAT RECOMMENDS THAT

PEOPLE NOT HAVE LONG-PEOPLE NOT HAVE LONG-TERM EXPOSURES ABOVE TERM EXPOSURES ABOVE

4.0 pCi/L4.0 pCi/L

04/11/23 Illinois Department of Nuclear Safety 11

IDNS RADON POLICY

The Illinois General Assembly declared effective July 30, 1997, that it is in the interest of the people of Illinois to establish a comprehensive program for determining the extent to which radon and radon progeny are present in dwellings and in other buildings in Illinois, at levels that pose a potential risk to the occupants and for determining measures that can be take to reduce and prevent such a risk.

04/11/23 12

Miner Studies

04/11/23 Illinois Department of Nuclear Safety 13

Working Level Month

The actual potential for contracting lung cancer increases with the dose received and the duration of exposure to a given dose.

A time and dose measure is used to quantify lung cancer potential. This is the Working Level Month (WLM).

Equivalent to 170 hours of exposure at 1 Working Level (WL)

04/11/23 Illinois Department of Nuclear Safety 14

Miner Studies Demonstrating Risk at Low Levels

Miner Cohort Aver. Cum. Exp. Risk Evident At

Czech Uranium Miners 3-300 WLM 50-99 WLM

Ontario Uranium Miners 40 & 90 WLM 40-70 WLM

New Mexico Uranium Miners 110 WLM 100+ WLM

Swedish Iron Miners 80 WLM 80+ WLM

Australian Uranium Miners 7 WLM 40+ WLM

Home Exposure at 4 pCi/L for 70 years = Cumulative Exposure of 54 WLM

04/11/23 Illinois Department of Nuclear Safety 15

Miners StudiesDemonstrating Non-Smoker Risk

Miner Cohort Aver. Cum. Exp. Risk Observed

Colorado PlateauUranium Miners

720 WLM 9-12 fold increaseStatistically Sig.

Swedish Iron Miners 80 WLM 10 fold increaseStatistically Sig.

Czech Clay ShaleMiners

32 WLM 10 fold increase NotStatistically Sig.

NM Navajo UraniumMiners*

1207 WLM 12 fold increaseStatistically Sig.

*Includes some smokers aver 3 cig/day - RR adjusted

04/11/23 Illinois Department of Nuclear Safety 16

NCI-Led Joint Analysisof Miner Data ('94)

Conclusions: Authors' estimates for U.S.:

– 15,000 lung cancer deaths/year 10,000 in smokers 5,000 in never-smokers

– Uncertainty Range = 6,000-36,000/yr. Linear dose-response. Little credible evidence for a threshold effect. Increased risk for nonsmokers confirmed. Higher risk associated with exposure received at low rates.

04/11/23 Illinois Department of Nuclear Safety 17

National Cancer InstituteJanuary 1997

Original miner-based estimates are on target for predicting indoor radon related lung cancer risks.

Long-term exposure to radon in U.S. homes may account for 6,000 to 36,000 lung cancer deaths per year.

“estimates of exposure response from homes are virtually the same as the extrapolations you get from miner studies….”

(Lubin, Boice)

04/11/23 Illinois Department of Nuclear Safety 18

Potential Confounders Other Mine Exposures

Close correlation of risk estimates despite presence of different environmental pollutants.

Increased lung cancer risk from radon:

– Regardless of silica dust levels,

– Regardless of arsenic levels,

– In absence of arsenic, chromium, nickel, asbestos,

– In mines without diesel engines,

– In mines without radioactive ore.

04/11/23 Illinois Department of Nuclear Safety 19

Translation of Miner Risk to Homes Risk Estimates

Dose per unit exposure in homes is 70% of that in

mines, due to lower respiratory rates.

14,000 deaths per year in US projected based

upon an average indoor radon concentration of

1.3 pCi/L.

04/11/23 Illinois Department of Nuclear Safety 20

Excess Lung Cancer Risk

LinearLinear No thresholdNo threshold Indicates no safe Indicates no safe

levellevel Many homes can Many homes can

provide similar provide similar accumulative accumulative exposures.exposures.

00.20.40.60.8

11.21.41.61.8

0 2000 4000 6000Cumulative Exposure (WLM)

% e

xces

s lu

ng c

ance

r de

aths

House at 200 pCi/LHouse at 200 pCi/L

House at 20 pCi/LHouse at 20 pCi/L

04/11/23 Illinois Department of Nuclear Safety 21

Who Has a Higher Risk Potential for Radon Induced Lung Cancer?

Case A:Person A: 5 years at an average of 10 pCi/L.

Person B: 15 years at an average of 4.0 pCi/L Case B:

Person A: 10 years at 4.0 pCi/L.

Person B: 4 years at 10 pCi/L.

Note if dose was given in WL one would simply convert to radon, using the equilibrium equation.

04/11/23 Illinois Department of Nuclear Safety 22

Lifetime Lung Cancer Risk Per 1,000 People (Refer to page 12 Citizens Guide)

20 pCi/L20 pCi/L 8 pCi/L8 pCi/L 4 pCi/L4 pCi/L 2 pCi/L2 pCi/L1.3 pCi/L1.3 pCi/L

88332211

<1<1

13513557572929151599

Non-Smoker Smoker Non-Smoker Smoker

04/11/23 Illinois Department of Nuclear Safety 23

“X” Years in Home at “Y” Radon to Equal 50 WLM Cumulative Exposure

0

5

10

15

20

25

30

35

40

45

0 10

20

30

40

50

60

70

80

90

Years in home

Avera

ge R

n in

hm

e(p

Ci/L

)

50 WLM is where excess lung cancer deaths observed in Ontario study.

Assumptions– 75% occupancy– 50% equilibrium

4 pCi/L4 pCi/L

04/11/23 24

Residential Risk Studies

Determining actual risk in homes

04/11/23 Illinois Department of Nuclear Safety 25

Residential Study Designs Cohort

– Identify population based on exposure – Follow for disease occurrence

Ecological – Compares level of disease and exposure in groups– Cannot correlate exposure to sick individual

Case-Control – Identify individuals with disease and individuals without disease– Look at and compare exposures

04/11/23 Illinois Department of Nuclear Safety 26

Swedish ResidentialCase Control Study

1360 cases, 2847 controls (male & female). Average Radon Concentration = 2.9 pCi/L. Compared to individuals whose home exposure averaged below

1.4 pCi/L. Found 30% increased risk with average home radon

concentrations of 3.8-10.8 pCi/L. Found 80% increased risk with average home radon

concentrations above 10.8 pCi/L. 2 separate control groups increases confidence in validity.

04/11/23 Illinois Department of Nuclear Safety 27

Canadian Case Control Study

750 cases, 750 controls (male & female).

Average radon concentration = 3.2pCi/L.

Found no significant increase in risk of lung cancer related to

radon exposure.

Lacks statistical power - limited by:– highly mobile population

– missing data (lack 40% of measurements initially targeted)

– large smoking confounder

04/11/23 Illinois Department of Nuclear Safety 28

NCI MissouriCase Control Study

538 Cases, 1183 Controls (all women). All Never Smokers or Long-Term Ex-Smokers. Average Radon Concentration= 1.6 pCi/L. (6.7% >4pCi/L). Over 63% cases deceased, next-of-kin interviews. Power of study: 80% chance of detecting a 40-55% increase. No radon/lung cancer association seen in total data. Statistically significant positive associations seen for cases with

"in person" interviews and adenocarcinoma.

04/11/23 Illinois Department of Nuclear Safety 29

Samet Editorial Re: NCI Missouri Study

Cautioned that residential studies "that showed no statistical significance for associations between radon and lung cancer cannot be interpreted as suggesting no risk of exposure to indoor radon."

Described residential studies as individually having "little prospect for characterizing the risk of exposure to indoor radon."

Warned: "Neither policy makers nor the public should look solely to the epidemiological studies of indoor radon and lung cancer in determining the imperative for risk management."

04/11/23 Illinois Department of Nuclear Safety 30

Finnish Nested Case - Control Study

1055 cases, 1544 controls (93% male). Average Radon Concentration = 1.8 pCi/L. Found no statistically significant risk of lung cancer from

indoor radon exposure. Authors acknowledged uncertainty over power of a single

study to detect effect expected based on miner studies. Differences in % deceased and % smokers between cases

and controls.

04/11/23 Illinois Department of Nuclear Safety 31

Other National Action Levels (pCi/L)

CountryCountry Existing HomesExisting Homes New HomesNew HomesUnited KingdomUnited Kingdom 5.45.4 5.45.4SwitzerlandSwitzerland 5.45.4 5.45.4SwedenSweden 5.45.4 1.91.9GermanyGermany 6.756.75LuxembourgLuxembourg 6.756.75CanadaCanada 2222

04/11/23 Illinois Department of Nuclear Safety 32

Problems with ResidentialRadon Studies

Lack of Statistical Power

– Increase statistical power by increasing # of cases.

Confounders

– Other causes can obscure radon/lung cancer

relationship. Smoking, heredity, diet, occupation, other air pollutants.

04/11/23 Illinois Department of Nuclear Safety 33

Problems with ResidentialRadon Studies

Limited access to previously occupied homes.

– Impedes accurate estimates of past exposures.

Estimation of past exposures from current

measurements.

– Physical parameters of house, home use, etc.

may have changed.

04/11/23 34

Residential Radon StudiesU.S. Public Health Service radon experts have estimated

at least 10,000-30,000 lung cancer cases plus twice as

many control individuals required to address the issue.

Eight residential studies completed involving a total of

4,941 cases.

CONCLUSION: Residential Studies Are Currently Not

Helpful for Radon Risk Assessment.

04/11/23 Illinois Department of Nuclear Safety 35

Summary

The current risk estimate is based on most complete and

extensive information currently available.

Less uncertainty than for most other pollutants since: – Based on human data.– Good understanding of general population's exposure.

Indoor radon poses a substantial risk.

Testing, mitigation, and the use of radon-resistant

construction techniques are prudent approaches.

04/11/23 Illinois Department of Nuclear Safety 36

Sources of Radiation Exposureto the US Population

Assumes average Assumes average indoor radon indoor radon concentration of 1.3 concentration of 1.3 pCi/L.pCi/L.

Radon is by far the Radon is by far the greatest single source greatest single source of radiation to the of radiation to the general public.general public.

RadonRadon55%55%

Medical X-RaysMedical X-Rays11%11%

OtherOther1%1%

InternalInternal11%11%

Nuclear MedicineNuclear Medicine4%4%

Consumer ProductsConsumer Products3%3%TerrestrialTerrestrial

8%8%

CosmicCosmic8%8%

04/11/23 37

Animal Studies

Confirm carcinogenicity of radon.Evidence of respiratory tract tumors observed in rats with cumulative exposures as low as 20 WLM.Exposure to ore dusts and diesel fumes, simultaneously with radon, did not increase incidence of lung cancer above that produced by radon progeny exposures alone. (DOE/OER 1988).

04/11/23 Illinois Department of Nuclear Safety 38

Carcinogenicity of Five Groups

Group A:

Group B:

Group C:

Group D:

Group E:

DemonstratedDemonstrated human carcinogen human carcinogenmustard gas, tobacco smoke, asbestos, benzene,mustard gas, tobacco smoke, asbestos, benzene,vinyl chloride, RADONvinyl chloride, RADON

Cause cancer in animals, Cause cancer in animals, probableprobable human carcinogen human carcinogenPCB’s, DDT, alar, chewing tobacco, cholesterolPCB’s, DDT, alar, chewing tobacco, cholesterol

Limited animal evidence, Limited animal evidence, possiblepossible human carcinogen human carcinogen

Inadequate evidence to classify (Saccharin)Inadequate evidence to classify (Saccharin)

Evidence of non-carcinogenicityEvidence of non-carcinogenicity

04/11/23 Illinois Department of Nuclear Safety 39

Regulatory Comparison of Radon to Other Group A Carcinogens

Always regulated.

Standard of exposure set at 1 death per 1,000,000 people/year.

Not regulated in home. Not regulated in home. Has been regulated in Has been regulated in mines since 1950’s.mines since 1950’s.

Present guideline of 4.0 Present guideline of 4.0 pCi/L estimates 28 deaths pCi/L estimates 28 deaths per 1,000,000 per 1,000,000 people/year.people/year.

Manmade Group A’sManmade Group A’s RadonRadon

04/11/23 Illinois Department of Nuclear Safety 40

Environmental Risk Comparisons

Pesticide ApplicationsPesticide ApplicationsHazardous Waste SitesHazardous Waste SitesToxic Outdoor PollutantsToxic Outdoor PollutantsPesticide Residues on FoodPesticide Residues on FoodRADONRADON

1001001,1001,1002,0002,0006,0006,000

14,00014,000

AnnualAnnualCancer DeathsCancer Deaths

04/11/23 Illinois Department of Nuclear Safety 41

Lung Cancer and Smoking

Assuming a population of 250,000,000 there are

158,000 lung cancer deaths per year in the U.S.

14,000 lung cancer deaths per year from radon.

81% to 95% of lung cancer deaths are primarily

from smoking alone.

04/11/23 Illinois Department of Nuclear Safety 42

Comparison of Radon to Other Causes of Death

25,00025,000

20,00020,000

15,00015,000

10,00010,000

5,0005,000

00 DrunkDrunkDrivingDriving

RadonRadon DrowningDrowning FiresFires AirlineAirlineCrashesCrashes

US EPA, NSCUS EPA, NSC

Ann

ual U

.S. D

eath

Rat

eA

nnua

l U.S

. Dea

th R

ate

04/11/23 Illinois Department of Nuclear Safety 43

“Radon is a SeriousNational Health Problem

American Lung Association American Medical Association Environmental Protection Agency National Academy of Sciences National Council on Radiation Protection and

Measurement U.S. Surgeon General World Health Organization

04/11/23 Illinois Department of Nuclear Safety 44

National Radon Health Advisory

“Indoor radon gas is a national health problem. Radon causes thousands of deaths each year. Millions of homes have elevated radon levels. Most homes should be tested for radon. When elevated levels are confirmed, the problem should be corrected.”

U.S. Public Health Service

04/11/23 Illinois Department of Nuclear Safety 45

Recent Analysis of Multiple Studies Confirm Risk-January 2, 1997

National Cancer Institute overall analysis

of several studies.

Rocky Mountain News, January 2, 1997Rocky Mountain News, January 2, 1997