Re: Dangers of Radon

["Otto G. Raabe" <ograabe@ucdavis.edu>]

February 20, 1998
Washington, DC

The NAS held a carefully orchestrated press conference which I attended
yesterday to formally release the new BEIR VI on Health Effects of Exposure
to Radon, which was funded by the EPA. Most of the key authors were
present. While the actual document will not be publicly available until
final printing in a few weeks, copies were made available to the press.
Priority was given to questions from the press. It was clear that the
authors had carefully prepared including the development in advance answers
to specific questions. Talking point summaries were apparently written
about these questions, some of which are reproduced below. In some cases
the author's remarks sounded a little repetitious. For example, whenever
the data was discussed, it was always described as "a rich data set".
Although the model used and believed to be correct by the key authors is a
linear dose-response model down to zero exposure, one of the authors, Roger
McClellan, noted that the inherent uncertainties do not rule out a
threshold model. He read this statement from a section of the report.
However, from them on the number of "deaths" caused by radon that the press
were told came from the linearized model.

The documents that are included below are: Opening Statement by Jonathan
Samet; Public Summary; Fact Sheet - Initial EPA Perspectives on BEIR VI
Radon Report; Q&A on Jay Lubin Study on Leukemia and Radon; Radon
"evergreen" Tip Sheet; Q&A's related to Dr. Bernard Cohen's Press Statement.

Otto
***************************

Health Effects of Exposure to Radon (BEIR VI)

Public Briefing
Feb. 19,1998

OPENING STATEMENT

Jonathan Samet

Professor and Chairman, Department of Epidemiology
Johns Hopkins University School of Hygiene and Public Health, Baltimore,

and

Chair, Committee on the Health Effects of Exposure to Radon
National Research Council


Good morning and welcome. We are pleased to present the findings of our
report examining the possible health effects of exposure to radon. This
report is the latest in a series of Research Council reports on exposure to
ionizing radiation. It reflects four years of work by a dedicated,
hard-working committee and staff.
A ubiquitous indoor air pollutant, radon in high levels has been known to
cause lung cancer in underground miners. Radon is not a brand-new public
health concern, but the data accumulated over the years now provide a much
stronger basis for assessing human health implications. More than a decade
ago, I served on a Research Council committee - the BEIR IV committee -
that developed a widely used model to estimate the health risks of radon
exposure. Since that time, substantial new scientific evidence has become
available. The Environmental Protection Agency, which develops guidelines
concerning indoor radon, asked the Research Council to review this new
information and develop an updated model for estimating health risks. Our
committee was not asked to make policy recommendations.
We spent nearly four years studying the issue. Our committee examined 11
epidemiological studies of underground miners, new data on lung cancer in
the general population, and the latest biological data on cancer and alpha
radiation, the kind of radiation ultimately released by radon that causes
injury to cells. We have held five workshops and a public meeting, have met
with scientists from the United States and abroad, and have examined
hundreds of peer-reviewed studies. We also have carefully analyzed large
data sets and developed approaches for characterizing uncertainty. The
report we are releasing today represents the consensus findings of the
committee and has undergone extensive peer review.
The committee concluded that radon is an important public health risk and
should be recognized as such. We estimate that radon contributes to about 1
2 percent of lung cancer deaths each year in this country, making it the
second leading cause of lung cancer behind smoking. In fact, smokers who
are exposed to radon appear to be at greater risk for developing lung
cancer because the effects of smoking and radon are more powerful when the
two factors are combined.
The committee developed two parallel but different models to estimate the
risks posed by radon. The models were based on analysis of data from the 11
studies of miners. Our assumptions were supported by studies of radon and
lung cancer in the general population and on molecular and cellular
evidence. Both models described lung cancer risk in relation to exposure,
but they differed in describing the rate of exposure. Both models accounted
for age and smoking habits.
Depending on the model used, we estimate that radon exposure contributed to
15,400 or 21,800 of the approximately 1 57,400 lung cancer deaths in 1995.
The majority of radon-related deaths occur among smokers, but 2,100 or
2,900 of radon-related lung cancer deaths each year - again depending on
which model is used - are non-smokers, those who have never smoked.
Although eliminating radon from all homes is an unrealistic and a
cost-prohibitive goal, reducing the level of radon in homes could prevent
some lung cancers in this country. Our committee estimates that about
one-third of radon-related lung cancer deaths that occur each year could be
prevented if radon levels in homes were reduced to at least 4 picocuries
per liter of air - the guideline suggested by the EPA. Most of these
preventable deaths would be among smokers. But by reducing levels of radon
in homes to the EPA level, perhaps 1,000 non-smokers might avoid lung
cancer too.
One question that many experts have struggled with is whether there is a
threshold of exposure below which levels of radon are harmless. Our
committee found no evidence that supports a threshold theory, but we were
not able to rule out the existence of a threshold. Most cancers are thought
to originate from damage to a single cell. The lowest dose of radiation
from radon exposure is a single alpha particle, which by itself may cause
substantial cell damage. Thus, radon might pose some risk even at very low
levels. Over the range for which observations can be made, for both smokers
and non-smokers, the data suggest that the risk of developing lung cancer
from radon is proportionate to the amount of exposure to radon. For
example, doubling the exposure doubles the risk, and cutting the exposure
in half cuts the risk in half. Our committee found that it is likely that
lung cancer is the only significant health hazard posed by radon.
Radon is one of the most extensively investigated human carcinogens, and
there is a substantial amount of scientific evidence available. However,
our committee acknowledges that our estimates are subject to several
important uncertainties. Miners inhale many other substances on the job,
and the majority of miners who were studied smoked. Disentangling the
effects of radon in miners from these other factors is difficult. In
addition, the miner population studied is all male, while in residential
settings, women and children also are exposed to radon.
The most direct way to assess the effects of radon in homes would be to
compare the levels of radon exposure among people who have lung cancer with
those who do not. Such studies have not yet provided a definitive answer
because levels of radon exposure in most homes are extremely small, making
it difficult to estimate the risks accurately. In addition, while it is
understood that the combined effects of radon and smoking create a greater
risk for people, that joint effect could not be fully characterized by the
committee. Even so, these uncertainties do not change the committee's
findings that lung cancer in the general population, including in smokers,
can be reduced by limiting exposure to radon. Of course, lung cancers in
smokers, including those attributed to radon, also can be reduced by
preventing smoking.
We would be happy to answer your questions. We will take questions from
reporters first and answer others as time permits. Please identify yourself
and your affiliation when you step to the microphone.

*********************************************************************

Public Summary:
The Health Effects of Exposure to Indoor Radon

Radon is a naturally occurring gas that seeps out of rocks and soil. Radon
comes from uranium that has been in the ground since the time the earth was
formed, and the rate of radon seepage is very variable, partly because the
amounts of uranium in the soil vary considerably. Radon flows from the soil
into outdoor air and also into the air in homes from the movement of gases
in the soil beneath homes. Outside air typically contains very low levels
of radon, but it builds up to higher concentrations indoors when it is
unable to disperse. Some underground mines, especially uranium mines,
contain much higher levels of radon.
Although radon is chemically inert and electrically uncharged, it is
radioactive, which means that radon atoms in the air can spontaneously
decay, or change to other atoms. When the resulting atoms, called radon
progeny, are formed, they are electrically charged and can attach
themselves to tiny dust particles in indoor air. These dust particles can
easily be inhaled into the lung and can adhere to the lining of the lung.
The deposited atoms decay, or change, by emitting La type of radiation
called alpha radiation, which has the potential to damage cells in the
lung. Alpha radiations can disrupt DNA of these lung cells. This DNA damage
has the potential to be one step in a chain of events that can lead to
cancer. Alpha radiations travel only extremely short distances in the body.
Thus, alpha radiations from decay of radon progeny in the lungs cannot
reach cells in any other organs, so it is likely that lung cancer is the
only potentially important cancer hazard posed by radon.
For centuries, it has been known that some underground miners suffered from
higher rates of lung cancer than the general population. In recent decades,
a growing body of evidence has causally linked their lung cancers to
exposure to high levels of radon and also to cigarette smoking. The
connection between radon and lung cancer in miners has raised concern that
radon in homes might be causing lung cancer in the general population,
although the radon levels in most homes are much lower than in most mines.
The National Research Council study, which has been carried out by the
sixth Committee on Biological Effects of Ionizing Radiation (BEIR) VI, has
used the most recent information available to estimate the risks posed by
exposure to radon in homes.
The most direct way to assess the risks posed by radon in homes is to
measure radon exposures among people who have lung cancer and compare them
with exposures among people who have not developed lung cancer. Several
such studies have been completed, and several are under way. The studies
have not produced a definitive answer, primarily because the risk is likely
o be very small at the low exposure encountered from most homes and because
it is difficult to estimate radon exposures that people have received over
their lifetimes. In addition, it is clear hat far more lung cancers are
caused by smoking than are caused by radon.
Since a valid risk estimate could not be derived only from the results of
studies in homes, the BEIR VI committee chose to use the lung-cancer
information from studies of miners, who are more heavily exposed to radon,
to estimate the risks posed by radon exposures in homes. In particular, the
committee has drawn on 11 major studies of underground miners, which
together involved about 68,000 men, of whom 2,700 have died from lung
cancer. The committee statistically analyzed the data to describe how risk
of death from lung cancer depended on exposure. In this way, the committee
derived two models for lung cancer risk from radon exposure.
In converting radon risks from mines to homes, the committee was faced with
several problems. First, most miners received radon exposures that were, on
the average, many times larger than those of people in most homes; people
in a few homes actually receive radon exposures similar to those of some
miners. It was necessary for the committee to estimate the risks posed by
exposures to radon in homes on the basis of observed lung cancer deaths
caused by higher exposures in mines. The committee agreed with several
earlier groups of experts that the risk of developing lung cancer increases
linearly as the exposure increases; for example, doubling the exposure
doubles the risk, and halving the exposure halves the risk. Furthermore,
the existing biologic evidence suggests that any exposure, even very low,
to radon might pose some risk. However, from the evidence now available, a
threshold exposure, that is, a level of exposure below which there is no
effect of radon, cannot be excluded.
The second problem is that the majority of miners in the studies are
smokers and all inhale dust and other pollutants in mines. Because radon
and cigarette smoke both cause lung cancer, it is complicated to
disentangle the effects of the 2 kinds of exposure. That makes it
especially difficult to estimate radon risks for nonsmokers in homes using
the evidence from miners. A final problem is that the miners were almost
all men, whereas the population exposed to radon in homes also includes
men, women, and children.
The committee used the information from miners and supplemented it with
information from laboratory studies of how radon causes lung cancer.  Then,
with facts about the US population, including measurements of radon levels
in homes, it estimated the number of lung-cancer deaths due to radon in
homes. In 1995, about 157,400 people died of lung cancer (from all causes
including smoking and radon exposure) in the United States. Of the 95,400
men who died of lung cancer, about 95% were probably ever-smokers; of the
62,000 women, about 90% were probably ever-smokers. Approximately 11,000
lung cancer deaths are estimated to have occurred in never-smokers in 1995.
The BEIR VI committee's preferred central estimates, depending on which one
of the two models are used, are that about 1 in 10 or 1 in 7 of all
lung-cancer deaths-amounting to central estimates of about 15,400 or 21,800
per year in the United States-can be attributed to radon among ever-smokers
and never-smokers together. Although 15,400 or 21,800 total radon-related
lung-cancer deaths per year are the committee's central estimates,
uncertainties are involved in these estimates. The committee's preferred
estimate of the uncertainties was obtained by using a simplified analysis
of a constant relative risk model based on observations closest to
residential exposure levels. The number of radon-related lung-cancer deaths
resulting from that analysis could be as low as 3,000 or as high as 32,000
each year. Most of the radon-related lung cancers occur among ever-smokers,
and because of synergism between smoking and radon, many of the cancers in
ever-smokers could be prevented by either tobacco control or reduction of
radon exposure. The committee's best estimate is that among the 11,000
lung-cancer deaths each year in never-smokers, 1,200 or 2,900, depending on
the model used, are radon-related lung cancers.
Radon, being naturally occurring, cannot be entirely eliminated from our
homes. Of the deaths that the committee attributes to radon (both
independently and through joint action with smoking), perhaps one-third
could be avoided by reducing radon in homes where it is above the action
guideline level (4 pCiL) to below the action levels recommended by the
Environmental Protection Agency.
The risk of lung cancer caused by smoking is much higher than the risk of
lung cancer caused by indoor radon. Most of the radon-related deaths among
smokers would not have occurred if the victims had not smoked. Furthermore,
there is evidence for a synergistic interaction between smoking and radon.
In other words, the number of cancers induced in ever-smokers by radon is
greater than one would expect from the additive effects of smoking alone
and 'don alone. Nevertheless, the estimated 15,400 or 21,800 deaths
attributed to radon in combination with cigarette-smoking and radon alone
in never-smokers constitute an important public-health problem.

***********************************************************

Feb. 19, 1998 --11:000 am
Fact Sheet: INITIAL EPA PERSPECTIVES on BEIR VI Radon Report

Key Messages:

* BEIR VI confirms EPA's position for the last decade that radon is the
second leading cause of lung cancer and a serious public health problem.

* NAS has estimated that 12% of lung cancer deaths in this nation are
linked to radon.  NAS' best estimates are that radon causes in the range of
15,000 to 22,000 lung cancer deaths each year.  EPA's best estimate has
been 14,000 annual lung cancer deaths due to radon.

* This report represents the most definitive accumulation of scientific
data gathered on radon since the NAS' BEIR IV report of 1988.  It affirms
once more that EPA's radon policies are well-grounded in strong science.

* NAS further noted that the data from radon studies in homes is consistent
with studies of radon health effects in mines and that lung cancer can be
reduced by limiting exposure to radon in homes. 

* NAS concluded that, although there is some uncertainty in these
estimates, lung cancer in the general population is an important public
health concern.

* The report concludes that many smokers will get lung cancer due to their
radon exposure which exacerbates the effects of smoking.

* The BEIR VI report found that even very small exposures to radon can
result in lung cancer.  In fact, NAS concluded that no evidence exists that
shows a threshold of exposure below which radon levels are harmless.

* EPA is committed to protecting the public's health.  EPA has in place a
voluntary program to find the homes with high radon levels.   We recommend
that people do a simple home radon test and if high levels of radon are
found, we recommend reducing those high levels with straight-forward
techniques.  

* EPA appreciates this latest comprehensive review of indoor radon science
from the National Academy of Sciences.  We thank NAS and the BEIR VI
Committee members for their commitment to this extensive undertaking.  

Question:	Shouldn't we  really be focused on tobacco smoke?
Response:	There is no question that if you quit smoking, you will reduce
your risk of lung cancer.  But reducing radon exposure is another confirmed
way to reduce lung cancer risk.  Smokers,  former smokers, and non-smokers
can all reduce their risk of lung cancer by reducing high radon levels.

Question:	Will BEIR VI  change EPA's radon policies?
Response:	It's too early for us to know the full impact of this report.
EPA will be taking a careful look at the report and consider all new
information.  EPA is pleased that this scientific report affirms the
current view that radon is a major public health concern.

**************************************************************

Feb. 19, 1998 -- 9am

	Q and A on Jay Lubin Study on Leukemia and Radon

Note: A study by Jay Lubin, from the National Cancer Institute, on the
relationship between radon exposure and a type of childhood leukemia was
released today.  He found no relationship.  You may get questions from
press or others that refer to this study, either in a straightforward way
or because the press or others are confused.  The purpose of this Q and A
is to help avoid that situation.

Question:

What is EPA's perspective about the study on radon released on Feb. 19 that
shows that there is no risk from radon?  

Answer:

That is a different study than BEIR VI, the major study released by the
National Academy of Sciences on February 19.  The study you are referring
to was a study led by Dr. Jay Lubin from the National Cancer Institute that
looked at the relationship between radon exposure and childhood leukemia.
The study is consistent with EPA's past position that the only known health
effect from inhalation of radon is lung cancer.  The NAS BEIR VI Committee,
on the other hand, found that radon is the second leading cause of lung
cancer and an important public health problem.  (Go on to other key
messages about BEIR VI.)

******************************************************

	RADON "Evergreen" TIP SHEET 		2/18/98 2:00pm
Millions of Americans are exposed needlessly to high levels of radon, a
radioactive gas, in homes without knowing it because radon is invisible and
although it can cause lung cancer, there are no immediate health symptoms.
			
Basic Facts
·  EPA and the Surgeon General recommend testing homes for radon to
determine if a home has a  
   high level of indoor  radon; only homes with high levels need further
action.
·  The average indoor radon level in U.S. homes is 1.3 picoCuries per liter
of air (pCi/L).
·  EPA has recommended a voluntary "action level" of 4 pCi/L.
·  EPA estimates about 6% (6 million) of U.S. homes will have levels at or
above 4 pCi/L.
·  More than 1 million homes have radon levels above 8 pCi/L.
·  More than sixty thousand home have radon levels above 20 pCi/L.
·  Since 1988: More than 11 million homes have been tested, more than
300,000 homes have been
   fixed, and more than 1.3 million new homes have been built radon resistant.

Key Messages to Debunk False Perceptions
Perception:	EPA's risk estimates have been exaggerated all along.	
Message:	The science behind radon's health risks has been thoroughly
reviewed and re-reviewed regularly by many experts; it's among the
strongest in the environmental field.  EPA stays on top of all the breaking
science on this issue from around the world.  We are not expecting the BEIR
VI report to present any "new surprises" about the science.  We believe the
radon science has always been strong and well-grounded, we it expect the
science to be even stronger with some added refinements.

·  EPA's current  risk estimates are based on the National Academy of
Science's risk model 
   (BEIR IV) and completely peer-reviewed by the Science Advisory Board. 
· NAS' Radon Risk Model is based on studies of  68,000 human subjects
(miners), not animal data. 
·  EPA's risk estimate of 14,000 lung cancer deaths/year is comparable to
NCI's estimate of 15,000
   deaths/year.
·  CDC, the Surgeon General's Office, AMA, NCI, ALA, WHO, NCRP and others
have identified
   radon as a serious public health risk.
·  Many Western European countries recognize radon as a health risk and
have radon action levels
   similar to U.S.'s including the United Kingdom, Germany, Sweden and Poland.
·  Radon health risks are high: 10 -2 for smokers and 10 -3 for
non-smokers.  Most environmental
   pollutants are regulated if risks exceed 10 -4 to 10 -6.

Perception:	EPA's radon reduction tactics are too aggressive.
Message:	EPA's indoor radon program is voluntary; EPA does not regulate
this risk.
·  EPA informs the public about the potential health risks of radon and
lets them make an individual choice.

Perception:	EPA's radon program is too costly to homeowners.
Message:	It's a personal and a voluntary decision for homeowners to choose
whether they spend money on this risk.  
·  EPA's and HHS' goal is to find the homes with high indoor radon levels.
The only way to know if a home has a high radon level is to test.  A
do-it-yourself home radon test devise can cost under $25.
·  Homes with high radon levels can be fixed with straight-forward
techniques that vent the gas to the outdoor air preventing it from building
up to high levels indoors.  The average cost to fix a home is about $1200.
New homes can be built to prevent radon entry for $300 or less.

************************************************

Q's and A's related to Dr. Bernard Cohen's Press Statement:

Question:
Dr. Cohen alleges that the National Academy of Sciences has not fully
considered his and others' research which shows that low levels of
radiation, including radon are not harmful, and in fact, may be beneficial.
 Has the NAS looked at Cohen's research?

Answer:
Dr. Cohen and is his work are well known to EPA and to the NAS.  The NAS
has BEIR VI Committee reviewed Dr. Cohen's work, however, you should talk
directly to the NAS about this.


Question:
Dr. Cohen's research appears to show that counties with high radon levels
have lower lung cancer rates.  What is your view of the conclusions of Dr.
Cohen's research?

Answer:
The value of "ecological" studies, which is the type of research that Dr.
Cohen does, was reviewed by The World Health Organization in 1994 and WHO's
report concluded that this type of research is not valuable for determining
the health effects of radon and does not shed additional light on this
topic.   In fact, WHO recommended that NO additional "ecological" research
be funded on radon health effects in homes.   All of the other leading
experts in this area have also concluded that ecological studies are not
the right method to define the relationship between radon and lung cancer. 

Question:
Dr. Cohen alleges that the reason EPA is regulating radon is, in part, to
justify other radiation standards which address lower exposures from
nuclear power and nuclear medicine facilities.  What is your response to this?

Answer:
EPA is encouraging public action on radon because high levels indoors can
pose substantial health risks to the public.  Dr. Cohen's perspective on
why we are encouraging public action in no way reflects our rationale.
Further, EPA is not regulating risks from indoor radon -- we are
implementing a voluntary program which encourages the public to take action.

********************************************

		*****************************************************
		Prof. Otto G. Raabe, Ph.D., CHP
                [President, Health Physics Society, 1997-1998]
		Institute of Toxicology & Environmental Health (ITEH)
		     (Street address: Old Davis Road)
		University of California, Davis, CA 95616
		Phone: 530-752-7754  FAX: 530-758-6140 [NEW AREA CODE]
		E-mail ograabe@ucdavis.edu