Dr. Richard Lemen: What you should know about asbestos

The first European
Asbestos Forum27th May 2015

Most asbestos comes from open-pit mines
using bench drilling techniques.
The term asbestos is traditionally attributed
to those forms used commercially.
Dr. RA Lemen

Vein of Asbestos
Serpentine Rock
Dr. RA Lemen

Milled Asbestos
Fibers are separated from the
core ore leaving the raw fibers
Dr. RA Lemen
Dry milling is most widely use.

Asbestos Use Dates Back 1000’s of years
“In the great civilizations of antiquity, whether in the East,
West, or in Europe generally, there was sufficient concentration
of the forces of labour to produce the intensest [sic] forms of
the maladies classed by Pliny as the “diseases of slaves.”
Some of the most injurious processes known to us now are
extremely ancient. To mention but a few: the textile
processes of preparing and weaving asbestos and flax.”
Adelaide M. Anderson, H.M. Principal Lady Inspector of Factories. Chapter II. Historical Sketch
of the development of Legislation for Injurious and Dangerous Industries in England. In:
Dangerous Trades, Ed. Thomas Oliver, John Murray, London, 1902.
Dr. RA Lemen

“Asbestos is one of the most marvelous productions of inorganic
nature.
It is a physical paradox, a
mineralogical vegetable,*
both fibrous and crystalline,
elastic and brittle; a floating
stone, as capable of being carded,
spun, and woven, as wool, flax, or silk.”
Occupying the apparent position of a connecting link between
the
mineral and vegetable kingdom, it would appear to possess
some of
the characteristics of both, while being altogether different from
either.”
R. H. Jones, 1897. Asbestos and Asbestic – Their properties, occurrence, and use.
Crosby Lockwood and Son, London, Preface Dr. RA Lemen

Top Asbestos Producers (USGS)
0
100,000
200,000
300,000
400,000
500,000
600,000
700,000
800,000
900,000
1,000,000
2011
2012
www.adao.us
World production of asbestos reached it’s maximum
in 1977 of 4.8 x 106 tons (Virta, 2002)

Year
2000
Is Production & Consumption Decreasing?
Dr. RA Lemen

0
500,000
1,000,000
1,500,000
2,000,000
2,500,000
Europe
Europe
NorthAmerica
NorthAmerica
Asia
Asia
Worldwide
Worldwide
1960 2000 1960 2000 1960 2000 1960 2000
Metrictons Worldwide consumption of asbestos in 1960 and 2000
From: Robert L Virta. Worldwide asbestos supply and consumption trends 1900 to 2000.
China consumes almost all of it’s own asbestos
India is the largest importer
Brazil exports about ½ it’s asbestos
Dr. RA Lemen

R. A. Lemen, Ph.D. 10
Ferruginous Bodies > Disease> Background Concentrations > etc.
As Consumption Goes Up Indicators of Human Exposure goup
Ferruginous
Bodies

88% Statistics from Upper Income countries
Time Trends May Indicate Shift Of Disease Burden Slowly
Shifting To Countries Using Asbestos Most Recently
Source: Stayner, Welch, Lemen,
2012

Asbestos
Diseases
Time
Are Asbestos Diseases Declining?
Developed Economies
Dr. RA Lemen

More information is available on the harmful effects of
asbestos, and more incontestable epidemiologic and
experimental evidence is available on its carcinogenicity,
than for any other environmental agent.
Dr. Lorenzo Tomatis, Former Director IARC.
Dr. RA Lemen

ASBESTOS-RELATED DISEASES
DISEASE ESTABLISHED CAUSAL
ASSOCIATION
Asbestosis 1930
Lung Cancer 1949-1955
Mesothelioma 1960-1963
Laryngeal Cancer 2006
Ovarian Cancer 2009
Colorectal reasonably anticipated
Stomach reasonably anticipated
Retroperitoneal fibrosis possibly
Ventilatory impairment unclear overall but restrictive impairment – yes
Dr. RA Lemen

“Asbestos’ effects often appear to be random”
Lung Cancer – 20 -25%
Mesothelioma – 7 -10%
Total Cancers – 35 -40%
 
Dr. RA Lemen

Vital Statistics
“Every death from asbestos-related diseases is avoidable”
Dr. Jakab, WHO Regional Director Europe
Asbestos is one of the most important occupational
carcinogens, causing about half of the deaths from
occupational cancer (WHO, 2014)
Exposures to asbestos occurs through inhalation of
fibres (WHO, 2014).
About 125 million people in the World are exposed at
the workplace and about 107,000 people die each
year from an asbestos-related disease. Worldwide this
burden of death is still rising (WHO, 2014).
[Note: this is about to be revised to 194,000]Dr. RA Lemen

Vital Statistics
“There is very little time left for that [to eliminate asbestos]”
Dr. Jakab, WHO Regional Director Europe
• 900 million living in Europe potentially Exposed or
1 in 3
• 15,000 deaths per year in Europe
• Mesothelioma deaths from just 15 European
countries cost society 1.5 billion euros yearly
• 37 of 53 European regional states have banned
• 16 European region countries still use asbestos
WHO, 2015 Dr. RA Lemen

~ Miscellaneous nonmetallic
mineral and stone Products
~ Ship and boat building
and repairing
~ Industrial and miscellaneous
chemicals
~ Other rubber products, and
plastics footwear and belting
ASBESTOSIS
most frequently recorded
by industry sector on death certificates
NIOSH
~ Petroleum refining
~ Electric light and power
~ Glass and glass products
~ Construction
~ Railroads
~ Blast furnaces, steelworks,
rolling and finishing mills
Dr. RA Lemen

 Plumbers, Pipefitter, & Steamfitters
 Managers and Administrators – No Epidemiology
 Electricians
 Carpenters
 Insulation Workers
 Laborers, Except Construction
 Supervisors, Production Occupations – No Epidemiology
 Welders and Cutters
 Janitors and Cleaners
 Truck Drivers – No Epidemiology
ASBESTOSIS
most frequently reported by Job title on death certificate
NIOSH
Dr. RA Lemen

~ Construction
~ Non-paid worker or non-
worker or own home/at
home
~ Elementary and secondary
schools
~ Industrial and
miscellaneous chemicals
~ General government
MESOTHELIOMA
most frequently recorded industry sector on death certificate
NIOSH
~ Agricultural production,
crops
~ Not specified manufacturing
industries
~ Electric light and power
~ Railroads
~ Hospitals
Dr. RA Lemen

~ Managers and Administrators
– No Epidemiology
~ Housewife/Homemaker
– No Epidemiology (except
take-home)
~ Plumbers, Pipefitters, &
Steamfitters
~ Janitors and Cleaners
~ Supervisors and Proprietors,
~ Sales Occupations
– No Epidemiology.
MESOTHELIOMA
most frequent Job title recorded on death certificate
NIOSH
~ Carpenters
~ Teachers, Elementary School
~ Farmers, Except Horticulture
– No Epidemiology
~ Electricians
~ Supervisors, Production Occupations
– No Epidemiology
~ Truck Drivers
– No Epidemiology
Dr. RA Lemen

Lamp Sockets Friction materials
Disk brake pads Gaskets
Gaskets Cement corrugated sheet
Non-roofing coatings Cement flat sheet
Roof coatings Clothing
Floor tiles Pipeline wrap
Cat Box fill Roofing felt
Automatic transmission components
vinyl floor tile
Up to 5,000 consumer products
contained asbestos
Examples:
From: U.S. Environmental Protection Agency, Feb. 3, 2015
Dr. RA Lemen

ASBESTOS-INDUCED DISEASES
Historical Perspective
Dr. RA Lemen

25
Numerous deaths (@50)
reported in a French asbestos
textile factory
Auribault, M., 1906. Note sur l’hygiene et la securite des ouvriers dans les filateurs
et tissages d’amiante. Bull Insp Trav, Paris Vol 14, p. 120 Dr. RA Lemen

Charing Cross Hospital London
Dr. Montague Murray Reported a
Case of Fatal Lung Disease in a 33
Year old Male Textile Worker during
Rounds at the Charing Cross Hospital In
1907. The patient had died in 1900.
Patient worked first 10 years in
carding Asbestos. He reported
he was only survivor of 10
workers he started with, who all
died around 30 years of age.
26
1907
Dr. RA Lemen

First x-ray descriptions of asbestos
induced Lung disease by Pancoast &
Pendergrass In the American Journal of
Roentgenology And Radium Therapy
In 1918 the Bulletin of U.S. Labor Statistics –
Reports both U.S. & Canadian Insurance
Companies would not insure Asbestos Workers
Due to unhealthy conditions in the Industry.
Dr. RA Lemen
1918.

Dr. William Edmund Cooke names the lung
disease caused by asbestos – Asbestosis - when
Describing the case of this disease in a 33 year
old woman named Nellie Kreshaw of Rochdale,
England.
Age 12 – worked in a cotton mill
Age 13 - worked at Garsides asbestos mill
Age 26 – worker at Turner Brothers Asbestos
in Spinning department
Age 33 – Died 06:30
14 March 1924
28
1927

First Epidemiology Study of Asbestos Workers Conducted
in the British Asbestos Textile Industry in 1930
finding 28.1 % of 374 workers with Pulmonary Fibrosis
(Asbestosis) and after 20 years of exposure 80 %.
The JAMA Reported results of the Merewether &
Price Epidemiology Study to American Physicians
29
1930

Trends are beginning to peak and level off in
Western Economies
Newly emerging economies trends for asbestosis are
climbing, i.e. India’s overall prevalence of asbestosis
was 11.5%
Dr. RA Lemen

Cancer & Asbestos
31
1935 Lynch and Smith (1935) in the United States and Gloyne (1935)
in the United Kingdom both associated occupational asbestos
exposure with lung cancer.
1936 Reports appeared in the medical literature of lung cancers occurring
in asbestos exposed workers (Egbert and Geiger, 1936 & Gloyne, 1936) .
1938 German physicians began calling lung cancer an occupational disease of
asbestos workers (Nordman, 1938).
1939 The UK Inspectorate of Factories report in the 1938 Annual Report
that 12 cases of lung cancer occurred among 103 cases of fatal asbestosis
or 11.6% (HMSO, 1939).
1942 Hueper (1942) in his classic book on cancer discusses asbestos related lung
cancers.
1949 In Factory Inspector’s Report of 1948 reports excess of lung cancer in both
men and women registered to have asbestosis.
Dr. RA Lemen

A 1955 study by Doll involved the
study of the mortality experience of a
cohort of 113 asbestos textile
workers employed more than 20
years.
Among this group, there were 11
lung cancer deaths observed
compared to only 0.8 expected,
when based upon the mortality
experience of England and Wales.
Over all studies the RR for lung
cancer has varied from 1.0 to 17.6
with an average RR of 9.8.
32
Lung Cancer
Dr. RA Lemen

Lung Cancer
The estimated mortality range estimates
are 43,000 – 344,000**
deaths annually
* Driscoll T et al, 2005. Am J Ind Med, Dec; 48(6): 419-431.
** Estimated based on applying McCormack et al, 2012. BJC, 106, 575-584.
The World Health Organization states the risk ratio (RR)
is 6:1 for contacting lung cancer vs. mesothelioma
following chrysotile exposure.***
*** World Health Organization. Chrysotile Asbestos. 2014.
Dr. RA Lemen

15
From: Markowitz S, 2012. Tail of Two Carcinogens: The Legacy of Asbestos and Smoking.
Ramazzini Days, October 26-28, Carpi, Italy.
34
Smoking & Lung Cancer Risk With Asbestos Exposure
Non-Smoker
Non-Smoker
Smoker
Smoker
Smoking Status Occupation Relative Risks Cancer Deaths
No Asbestos 1
Asbestos
Worker 5.2
No Asbestos 10.3
28.4Asbestos
Worker
Asbestos plus smoking raise risk of lung cancer additively
Asbestosis plus smoking raise lung cancer supra-additively Dr. RA Lemen

15
Asbestos alone raises the risk of lung cancer
35
1. Squamous Cell
3. Adenocarcinoma
2. Small (oat) Cell
4. Large Cell
35%
25%
25%
15%
Incidence of Cell Types in Lung
Cancers
Dr. RA Lemen

Lung Cancer
While not possible to directly estimate asbestos-related lung
cancer estimates between 1 and 8 excess lung cancer cases
for each mesothelioma
Source: McCormack et al, 2012. BJC, 106, 575-584
Dr. RA Lemen

Mesothelioma and Asbestos
“The pathological diagnosis of mesothelioma has been beset by more difficulties than has any
other industrial cancer.”
Ian Webster, 1977. Methods by which mesothelioma can be diagnosed. In: Asbestos Symposium, Johannesburg, H.W. Glen (ed.), Department
of Mines, National Institute for Metallurgy, Randburg, SA.
1927 association between mesothelioma and asbestos, however,
not publish it until 1955
1934 Gloyne reports on a case of lung cancer with “a few deposits
of
growth in the pleura”1943 Reports of pleural (chest) and peritoneal (abdominal) tumors
associated with asbestos exposures. The first mesothelioma
was in a case of asbestosis in Germany.
1947 - 1960
During this time over a dozen more mesothelioma reported
in the worlds scientific literature including two from the
Canadian chrysotile mines.
Dr. RA Lemen
From: Lemen, 2012

Dr. RA Lemen
Dr. J.C. Wagner
Fibers end up
here where tumor
develops
33 (22 men, 11 females) cases of
mesothelioma occurring between
1956 and 1960 in miners, millers, and
transporters of asbestos and of non-
mining residents of crocidolite in the
N. West Cape Province of S. Africa .
1960

Carried out the first epidemiological study of asbestos
Workers to identify mesothelioma.
Found Mesothelioma, lung cancer and asbestosis in excess
in an asbestos manufacturing plant in Ohio.
He identified by Death Certificate 19 lung cancers (3.4: 95% CI =
2.0-5.3); 28 asbestosis; and upon evaluation of death record found
7 mesothelioma, 25 lung cancers and 30 asbestosis cases.
Dr. Thomas F. Mancusco
Phillip-Carey Plant Loveland, OH @ 1968
USPHS Photos
Dr. RA Lemen
1963

First to conduct a large scale mortality study of
end-product users of asbestos from records of
asbestos union members.
Found asbestos end-product Workers were at risk
of asbestosis; lung cancer; mesothelioma; and
gastrointestinal cancers.
Reocgnized guidance limit was far too High.
Dr. RA Lemen
1964

Dr. RA Lemen
Occupational exposure to all forms of asbestos has resulted
in a high incidence of lung cancer, pleural and peritoneal
mesothelioma, gastrointestinal tract, & excess of cancers of
the larynx.
Mesotheliomas also occur in individuals living in the
neighborhood of asbestos factories and crocidolite mines
and in household contacts of asbestos workers.
Both cigarette smoking and occupational exposure to
asbestos fibres independently increase lung cancer & act in a
multiplicative fashion when combined.
The general population may also be exposed to asbestos
fibres in air, beverages, drinking-water, food and
pharmaceutical and dental preparations & consumer use of
asbestos-containing products.
At present, it is not possible to assess whether there is a
level of exposure in humans below which an increased risk of
cancer would not occur.

The Lancet Editorial
December 6, 2008
Mesothelioma mortality in developed countries
have increased over the last 20 years, according to
high rates of exposure to workers in the 1960s.
125 million people are currently at risk from
asbestos and there are about 90,000 asbestos-
related deaths per year.
Dr. RA Lemen

Mesothelioma – Estimated 43,000 die annually
Worldwide Age Standardized Mesothelioma
Incidence Rates/100,000 for Males, 1998-2002
Dr. RA Lemen

Time trend in age-adjusted mortality rate for pleural and
peritoneal mesothelioma, worldwide, 1994-2008
From: Delgermaa et al, 2011. Global mesothelioma deaths reported to the World
Health Organization between 1994 and 2008. Bull World Health Org, 89:716-724C.
Dr. RA Lemen

World Asbestos Disease Estimates
Mesothelioma
Highest / 100,000
Italian Genoa Province – 5.8
West Cape Australia – 4.7
Northern Yorkershire – 4.2
Northern Ireland – 4.0
Scotland – 3.6
U.S. - 0.9 [pleural only] M/F Mean Age
Worldwide = 4.9 3.6:1 70.0
UK highest = 17.8 5.7:1 71.3
Australia = 16.5 5.4:1 71.3
Italy = 10.3 2.4:1 71.2
U.S. = 5.0 4.2:1 72.8
Sources: Stayner, Welch,
Lemen, 2013; Delgerman et al,
2011; Bianchi & Bianchi, 2007
Dr. RA Lemen

Mesothelioma Incidence
Stayner L, Welch LS, Lemen R, 2013
46

Main Asbestos Fiber Types of Commercial Importance
Amosite - Brown Crocidolite-
Blue & straight
Anthophyllite
brittle, white fibers
Chrysotile - White
fine, silky, flexible
95% of all asbestos 5% of all asbestos consumed
straight, brittle fibers
Tremolite and Actinolite, Anthophyllite is found mainly as a contaminant in other minerals. RALemen

AMPHIBOLES
The Big Three made up about 5% of all asbestos
commercially used
Anthophylite Amosite crocidolite
While its evil cousin Tremolite is
blamed as the toxic contaminate
of chrysotile and thus makes
chrysotile toxic.
TremoliteDr. RA Lemen

Anthophyllite Asbestos
Earliest Used Form of Asbestos @2500 b.c.
1965 – Lung fibrosis with short latency
1974 – Lung Ca SMR 3.33 (95% CI: 1.44 - 6.57)
No Mesothelioma
1989 – 6/14 mesothelioma reported in Finland with
anthophyllite predominate
1994 – 4 mesothelioma among
736 anthophyllite miners
and millers
Mined
Finland 1915 - 1975
Japan 1883 - 1970
Main uses in cement, insulation, roofing material
First Disease Findings

Amosite Asbestos
Asbestos Mines of South Africa
(cummingtonite-grunerite asbestos)
First mined @ 1919
1964 – First clinical study - Asbestosis prevalent,
few lung cancer, no mesothelioma.
1972 – First Cohort Study – 933 males
in New Jersey plant reported
5 mesotheliomas observed
(2 pleural; 3 peritoneal)
[Selikoff IJ, Hammond EC, Churg J, 1972. Carcinogenicity of Amosite Asbestos. Arch
Environ Health. 25, Sept., 183-186]
Patterson , NJ

Crocidolite Asbestos
First exported @1893 from S. Africa
1960 – First case series of mesothelioma – reported 33 cases (22 males, 11
females; ages 31 to 68) all but one exposed to crocidolite
1988 – First Cohort Study in Australia at Wittenoom –reported high
mesothelioma rate
1978 – First epidemiology study of workers of gas mask workers
R Lemen Photo S. Africa 2009

CHRYSOTILE ASBESTOS
• FIBERS SEPERATING
FROM THE MINERAL
Chrysotile represented over 95% of
all asbestos in commercial products.
Chrysotile is the only type of asbestos mined today.
What do we know about the only
Asbestos type still being Sold?

Chrysotile asbestos discovered in
Quebec in 1860. Mining started in 1878.
Canada had world’s first commercial mines.

White Gold Pioneers: Asbestos Mining
• (Asbestos mine at black Lake @ 1890s – White
Gold Pioneers: Asbestos Mining: McCord
Museum)
Canadian Chrysotile Asbestos Mine at Black Lake @ 1890s McCord Museum.
Dr. RA Lemen

Chrysotile production began in Russia as a result of its
discover in 1712 in the Ural Mountains (Carroll-Porczynski, 1956).
Russian Asbestos Mine
Russian Asbestos Bagging
Man Standing in Asbestos
U.S. Public Health Service Photos - 1994
Russia commands 60% of the world market
Dr. RA Lemen

What happens when we breath in asbestos fibers?
Dr. RA Lemen

Nose Filters out
fibers >100µ long
Cilia Clears mucus
(and fibers) from lung
Free Alveolar Macrophages
(FAMs): Phagocytize fibers within
lung
How does our body react to the presence of asbestos fibers?
Lung Ca
Mesothelioma
Dr. RA Lemen
Asbestosis

Bio-persistence
Amphiboles are much
more bio-persistent in the
lung than Chrysotile.
The amphibole
contaminate of
chrysotile, tremolite
remains in the lung long
after chrysotile has moved
into other body areas like
the pleura.
Dr. R.A. Lemen
Do All Asbestos Fiber Types React The Same O

Chrysotile and Bio-persistence
Mesothelial cells have the unique characteristic
of engulfing anything, whether a solid, liquid,
or gas.
Similarly, mesothelial cells phagocytize
asbestos fibers.
Source: Yamashita et al., 2013. J Clin Biochem Nutr; 53(1): 27-35.,
Dr. RA Lemen

0
5
10
15
20
25
30
35
40
45
50
1
No exp. <0.1 med >1.0
9.2
17.9
46.3
OR
Rödelsperger et al, 2001. AJIM, 39:262-275
Multiple studies confirm, as exposures continue,
relative risk of asbestos-related mesothelioma increase.
[OR = Odds Ratio]
Dr. RA Lemen

Where Does Mesothelioma Occur
Pleural Mesothelioma
Mesothelioma
develops
in the two layers of
the
pleura
Tumor then spreads to covers
the lung in a thick sack that squeezes and suffocates as
Remaining
Lung
Dr. R.A. Lemen

Where Does Mesothelioma Occur
Peritoneal Mesothelioma

So Is Exposure to Chrysotile Safe?
Dr. RA Lemen

In human lung tissue, amosite
fibers were greatest in number
followed by chrysotile,
crocidolite, tremolite/actinolite,
and anthophyllite.
BUT
In mesothelial tissues, chrysotile
fibers were 30.3 times more
common than amphiboles.
Suzuki & Yuen, 2002 Asbestos fibers contributing to the induction
of human malignant mesothelioma. Ann N Y Acad Sci.
Dec;982:160-76.
Dr. R.A. Lemen
FACTS

CHRYSOTILE –Early Medical Findings
Dr. Cartier, mining company
doctor, reported two cases of
pleural mesothelioma, one
with minimal asbestosis; the
other with no asbestosis,
among 4,000 asbestos
workers seen at the Thetford
International Clinic in
Quebec.
Mesothelioma
1952
[Cartier P, 1952. Abstract of discussion.
Arch Ind Hyg Occup Med: 5; 262]

From Cartier P, 1955. Some
clinical observations of
asbestosis in miners and mill
workers. Arch Indust Health. 11:
204-207.
CHRYSOTILE
Early Medical Findings
Cartier, reported among the 4000
workers between 1945 and 1953 –
128 with asbestosis
Thetford Mine Mill
1955

CHRYSOTILE -
early Medical Findings
Thetford medical officer informs a visiting British industry
physician that he had observed 126 workers with pleural plaques
and that 93% of them had signs of asbestosis.
The communication was kept confidential.
[From Greenberg M, 2005.
1963

CHRYSOTILE
Early Medical Findings
Rossiter reported a high
prevalence of various
abnormal radiological
changes among miner and
millers from Thetford-
Mines.
R. A. Lemen, Ph.D.
1972

Results of an epidemiological study
of an 1891-1920 birth cohort of Quebec
chrysotile miners in Canada published.
Excess mortality was found in the
Canadian miners.
CHRYSOTILE - Early Epidemiology
From: Nayebzabeh et al. 2001.
1980
Canadian Miners

Follow-up of the original study
found the SMR of lung cancer
rose from 1.25 to 1.39, and
deaths from mesothelioma
also increased.
FromNayebzabeh et al. 2001.
CHRYSOTILE-
Early Epidemiology
1993
Thetford-Mines (Québec)]

International Labour Organization
CHEMICAL DATA SAFETY CARDS
Asbestos, chrysotile ICSC: 0014
White asbestos
Serpentine chrysotile
CAS No:2001-29-5
RTECS No: CI6478500
UN No: 2590
EC No: 650-013-00-6
Mg3Si2H4O6 / Mg3(Si2O5)(OH)4
Molecular mass: 554
IPCS
International
Programme on
Chemical Safety Prepared in the context of cooperation between the International Programme on Chemical
Safety and the European Commission
© IPCS 2004
What Is The Scientific Consensus
About the One Asbestos Fiber Type Still Mined & Sold?

 Effects of long-term or repeated exposure -
The substance may have effects on the lungs, resulting
in pulmonary fibrosis and mesothelioma. This
substance is carcinogenic to humans.
 The recommendations on this Card also apply to
other forms of asbestos.
Avibest C, 7-450 asbestos, Calidria RG 144, Calidria RG
600, Calidria RG 100, Hooker no.1 chrysotile asbestos, K
6-30, Plastibest 20, RG 600, 5RO4, Sylodex, Cassiar AK,
Cassiar A 65, Fritmag, P 3-50 and P 4-20 are trade names.
International programme on chemical Safety
Prepared in the context of cooperation between the International Programme on Chemical Safety and the European Commission
© IPCS 2004

 These findings along with the results of the experimental studies
leave no doubt that the scientific evidence supports the
carcinogenicity of chrysotile alone in the induction of
mesothelioma
 The debate, as it applies to human exposure to pure
chrysotile containing products is academic, at best, as
there appear to be few if any pure chrysotile deposits
unequivocally identified or reported in the scientific literature
 Nor have any products purported to contain only chrysotile
been conclusively shown to contain uncontaminated pure
chrysotile.

However, if and when such deposits or products are
identified, the fact remains that chrysotile alone can cause
mesothelioma, as demonstrated in this lecture, when
applying the existing scientific knowledge into the
parameters of the Hill Causation Model
The exact potency of chrysotile, per dose to cause
mesothelioma, when compared to the amphiboles, remains
controversial and has been discussed in various other papers
(Stayner et al, 1976; Hodgson JT & Darnton A., 2000;
Landrigan et al, 1999 & IPCS, 1998)
However, even when potency, on a dose by dose basis, is
considered the fact remains that chrysotile is capable of
causing mesothelioma and that no safe dose has been
identified below which a risk of developing mesothelioma
exists.

Scientific and Governmental Agencies conclude all commercial types of asbestos cause
Mesothelioma
WHO EPA
Surgeon General of the United States
World Trade
Organization
National Academy of Science
Rr. RA Lemen

IS
POLITICAL
NOT
SCIENTIFIC
CHRYSOTILE ASBESTOS CONTROVERSY
OVER MESOTHELIOMA

Science is the Art of Disproving Hypotheses
Dr. RA Lemen

White Swan Hypothesis:
Chrysotile does not cause mesothelioma
Dr. RA Lemen

The White Swan Hypothesis:
Chrysotile does not cause mesothelioma
Studies that conclude that exposure to chrysotile
causes mesothelioma
Is disproved by the finding of Black
Swans:
Dr. RA Lemen

“Potency differences for predominantly chrysotile
versus amphibole asbestos-exposed cohorts become
difficult to ascertain when meta-analyses are restricted
to [in] studies with fewer exposure assessment
limitations.”
Dr. RA Lemen

Arguments
regarding
Chrysotile Asbestos
are driven by
Economics
not Science Dr. RA Lemen

73
Header Goes Here
Graham W. Gibbs and Geoffrey Berry
Chapter 4. Epidemiology and Risk Assessment2008
` EPIDEMIOLOGY AND RISK ASSESSMENT
107
replaced by acetone clearing. When modern quality control methods and sample density rules were introduced, the fiber concentration
became 3200 f/mL.
Host and Environmental Considerations
The third category of parameter influencing risk estimates includes smoking, as well as other host and environmental variables. Selikoff
et al. (1968) first reported a synergistic effect between asbestos and smoking in the causation of LC, and this observation was confirmed
by Berry et al. (1972). In a later follow-up Berry et al. (1985) found that "overall nonsmokers have a RR of LC due to asbestos exposure
1.8 times that of smokers." More recently, Liddell (2001a) concluded, "the RR of LC from asbestos exposure is about twice as high in
nonsmokers as in smokers." His conclusion was not without controversy since in another review, Lee (2001) stated, "asbestos exposure
multiplies risk of LC by a similar factor in nonsmokers and smokers." The work of Liddell (2001a) was extended by Berry and Liddell
(2004) who concluded, "The excess RR for LC from asbestos exposure is about three times higher in nonsmokers than in smokers," and
"If interactions are present the RR from exposure changes only slightly between light and heavy smokers, but is higher (in the former than
the latter). The RR estimated from epidemiological studies of a mixed population of nonsmokers and smokers applies to smokers."
In some areas, radon in homes is elevated. While debated, radon and radon daughters are now established carcinogens (Darby et aI.,
1998). This factor has not been generally taken into account in asbestos risk estimations.
The effect of not taking confounding, or modifying factors into account could lead to either an underestimation or an overestimation of
the risk ascribed to asbestos, but an overestimation of risk is more likely, since in practice coexposures tend to correlate positively.
_ Thresholds of Risk
There are levels of exposure below which asbestosis resulting from exposure does not occur, but estimates of thresholds differ. It is
debated whether there is a threshold below which there is no increase in risk of LC and MM (Browne and Gibbs, 1998). A linear dose-
response relationship between RR and exposure is often used as "a widely accepted and scientifically reasonable compromise rather than
an established scientific principle" (HEI-AR, 1991). Hodgson and Darnton (2000) noted that "direct statistical confirmation of a threshold
from human data is virtually impossible," and used a nonthreshold model. Browne (2001) criticized these authors, while Liddell (2001b),
noted, "nonlinearity is extremely difficult to detect epidemiologically, especially at low levels of exposure."
While it might seem prudent for regulators to assume a linear risk through zero in the absence of proven evidence, it is argued that
such an assumption is contrary to what is known about the interaction of asbestos with the respiratory tract. For example, not all fibers in
the air are inhaled or penetrate into the lung. It is necessary for fibers to get to the pleura to cause disease, some fibers dissolve and are
eliminated and the majority deposit proximally in the respiratory tract. Fibers are coated by biological fluids that may serve to protect the
lung. There are DNA repair mechanisms that provide protection in the event genetic damage occurs. Taken together, it is highly
improbable that there is a finite risk at close to zero exposure and it seems reasonable to conclude that thresholds exist.
It is necessary for
fibers to get to the
pleura to cause disease
. . .
Even the Scientists That
Negate the Role of Chrysotile
Have to Admit:
Dr. R.A. Lemen

Chrysotile Asbestos
Obscure the Facts
Create
Doubt
Dr. R.A. Lemen
However

From: Lemen RA, 2008. Smoke and Mirrors: Chrysotile asbestos is good for your – Illusion and confusion but not fact. In: India’s
Asbestos Time Bomb, Eds. David Allen and Laurie Kazan-Allen, IBAS, London, September.
Dr. RA Lemen

Low Dose Exposure How Low Does
It go!!!!
Asbestos
&
Mesothelioma
Are Low and
Background
Exposures Safe?
Dr. RA Lemen

Background Exposures
do not cause
Mesothelioma
have not been proven to
cause
Mesothelioma
Rather
Dr. RA Lemen

What We Do Know About
+
Background
Exposures
Occupational
Exposures
=
Increased
Risk
(total dose)
Dr. RA Lemen

91
The Helsinki Consensus Report on Diagnosis and Attribution
Scand J Work Environ Health 1997; 23: 311 – 318
The following points need to be considered in the assessment
Mesothelioma can occur in cases
with low asbestos exposure.
However
Very low background
environmental exposures carry low
risk.
Dr. RA Lemen

92
Non-Mutagenic Agents
For non-mutagenic agents it is assumed there is some
level that is incapable of causing harm otherwise
known as a threshold.
Threshold
exposure
Number
of cases
Dr. RA Lemen

Most oncogenes are mutations . . .
The existing evidence suggests that asbestos fiber-induced
carcinogenicity involves both mutagenic and nonmutagenic
mechanisms or both.
From: Huang SXL et al, 2011. Role of Mutagenicity in asbestos fiber-induced carcinogenicity and other
diseases. J Toxicol Environ Health, Part B. 14: 179-245.
Dr. RA Lemen

Conclusions on thresholds for
non-mutagenic agents cannot
be applied for mutagenic
agents.
Asbestos Causes Mutations
Dr. RA Lemen

{
Dose
Response
The more someone is exposed, the greater
the risk
Linear Models of Dose Response have
been around for years and are generally
accepted (NRC, 1984)
Mesothelioma is caused by asbestos fibers
reaching the pleura – the location of
target cells for mesotheliomaRichard A. Lemen, Ph.D.
Assistant Surgeon General
USPHS (Ret.)
Dr. RA Lemen

{
Dose
Response
Exposure
Disease
Linear Dose Model
Dr. RA Lemen

Non-Linear Dose Response Curve
LOW DOSE THRESHOLD
HIGH DOSELOW DOSE
NUMBER
OF CASES
OF DISEASE
EXPOSuRE
Unknown
Susceptible
?
Dr. RA Lemen

The Higher the Exposure the
Shorter the Latency
The Lower the Exposure the
Longer the Latency
Dose
Fiber/yrs
Latency in Years
0 10 20 30 40 50+
25
1000
2000
Dr. RA Lemen
The data for the most heavily exposed
people as well as those for the groups
with the lowest exposures are exactly
the same as would be expected, if an
inverse correlation exists between
the intensity of exposure to asbestos
and the duration of latency period.”
Bianchi, Latency periods in asbestos-related
mesothelioma of the pleura, European Journal of Cancer
Prevention, VOL. 6, 1997, p. 164, Supp. Ex. 17

Each Exposure Shortens The Latency
Period For Mesothelioma
“Latency time was also dependent on
exposure, varying from 29.6 years for
insulators (with the highest exposure) to
51.7 in women with domestic exposure.”
Hillerdal, Mesothelioma: cases associated with non-occupational and low
dose exposures, Occup Environ Med 1999; 56: 505-513, p.509
Dr. RA Lemen

{
Low Dose
Exposure
You do not need to be exposed to
a lot of asbestos to get mesothelioma.
Chrysotile
asbestos
Dr. RA Lemen

{
Low Dose Exposure
Richard A. Lemen, Ph.D.
USPHS (Ret.)
In a person with multiple exposures to
asbestos, ALL of them contributed to increase
the risk of developing mesothelioma.
+
=
+
=
+
Dr. RA Lemen

Low Dose Exposure
Richard A. Lemen, Ph.D.
USPHS (Ret.)
You cannot isolate any particular exposure to
asbestos and hold it HARMLESS in the causation of
mesothelioma.
+
+
=
+
Dr. RA Lemen

103
Mesothelioma has occurred
following short term asbestos
exposures of only a few weeks, and
can result from very low levels of
exposure.
Dr. RA Lemen

Documented cases of asbestos-related
diseases have occurred when the only
apparent exposure has been shaking and
laundering of the clothing of an exposed
worker.
Take-home exposures
Amphibole
Asbestos
Dr. RA Lemen

105
Dr. RA Lemen
United States Occupational Standard For Asbestos Does Not Eliminate Risk
Department of Labor, Occupational Safety and Health
Administration, 29 CFR Parts 1910, 1915 and 1926,
Occupational Exposure to Asbestos, Final Rule, Federal
Register, Vol. 59, No. 153, August 10, 1994
The 0.1 f/cm3 level leaves a
remaining significant risk.
3-4/1,000
Dr. RA Lemen

106
Lifetime Risk of Mesothelioma at Low Cumulative Doses of Asbestos
0.0004 fibers/cm3 (Median Dose) X 73 years
lifetime exposure
= 0.0292 f/cc/years of exposure
(9 per million lifetime risk)
Breslow, L, (Chair), et al., 1984. Asbestiform Fibers –Nonoccupational Health Risks,
National Academy of Sciences; Table 7-2.: 212 .
0.002 fibers/cm3 (High Dose) X 73 years lifetime
exposure
= 0.146 f/cc/years of exposure
(46 per million lifetime risk)
Dr. RA Lemen

Iwatsubo Case Control Study on Dose-Response at Low Levels
Asbestos Cases Controls OR 95% CI
Exposure
Intermittent
<0.5 66 98 1.1 (0.8-1.7)
.05-0.99 19 8 4.0 (1.7-9.7)
1-99.9 48 21 4.0 (2.2-7.2)
≥ 10 17 5 5.9 (2.1-16.7)
Continuous
<0.5 11 11 1.9 (0.8-4.8)
0.5-0.99 10 4 4.6 (1.4-15.4)
1-9.99 32 6 9.2 (3.7-23.1)
≥ 10 32 5 11.3 (4.1-30.7)
Am J Epidemiol Vol.
148, No. 2, 1998
Dr. RA Lemen

cases controls OR 95% CI
Cumulative exposure up to end of observation (fiber years)
not exposed 11 67 1
>0-0.15 14 12 7.9 2.1-30.0
0.15-1.5 38 25 21.9 5.7-83.8
1.5-15 46 16 47.1 11.5-19.3
>15 16 5 45.4 8.1-257
Cumulative exposures up to 10 years before end of observation
not exposed 11 67 1
>0-0.15 15 13 7.9 2.1=29.5
0.15-1.5 39 24 24.0 6.2-93.0
1.5-15 45 16 51.8 12.4-216
>15 15 5 42.6 7.3-249
Cumulative exposure up to 20 years before end of observation
not exposed 14 68 1
>0-0.15 15 13 9.2 2.4-35.0
>0.15-1.5 44 24 20.5 5.8-72.6
>1.5-15 40 16 32.2 8.5-122
>15 12 4 43.8 7.1-269
Rödelsperger et al, 2001. AJIM, 39:262-275
Mesothelioma & Exposure – German
Hospital-Based Case-Contorl Study
Dr. RA Lemen

109
kk
Asbestos and Man-Made Vitreous Fibers as Risk Factors for Diffuse Malignant Mesothelioma: Results From a German
Hospital-Based Case-Control Study, Claus Rodelsperger, DSC, Karl-Heinz Jockel, PhD, Hermann Pohlabeln, MSC, Wolfgang
Romer, MA, and Hans-Joachim Woitowitz, MD, American Journal of Industrial Medicine 39: 262-275 (2001)
…our results confirm the previously
reported observation of a distinct
dose-response relationship even at
levels of cumulative exposure below
1 fiber year. (p. 262)
Conclusion of German Study
Dr. RA Lemen

Initial vs. Continuous Exposure
Asbestos is a complete carcinogen,
Which means
It can both initiate and promote cancer
Therefore
Persistence exposure after initial exposure can
not be discounted or irrelevant.
Tomatis et al, 2007. Int J Occup Environ Health, 13:64-69; Governa et al, 1999. J Toxicol Environ Health A, Nov. 12, 58(5): 279-287.

In Conclusion -
Dr. RA Lemen
Delgermaa et al., 2011 & Lemen, 2012

In Conclusion -
Is Production and Consumption Decreasing?
Chrysotile is the only form being commercially
exploited
Use decreased by Bans and Regulations have severely
restricted exposures in those with them
Brazil, China, Kazakhstan, and Russia still exploit
chrysotile’s use
Consumption Increasing in developing countries
Dr. RA Lemen

Chrysotile is not Safe
Evidence currently suggest a lower risk for
mesothelioma than from equal doses of
amphiboles, but as better exposure data becomes
available this difference becomes less.
Asbestosis and lung cancer risks are similar.
There is no form of safe asbestos.
Dr. RA Lemen
In Conclusion –

In Conclusion -
High exposures still
occur in developed
countries
Very high exposures in
developing world, although
data is limited
Dr. RA Lemen

In Conclusion -
Iceland first banned asbestos in 1983, now more than
50 countries have banned
The pace of bans has slowed over the past decade with
some withdrawing their bans and other have extended
the timeframe for implementation.
This is an indication of the success of
the pro-chrysotile lobby
9 of 10 of the most populous countries, all major
past or present users of Asbestos have yet to
adopt bans.
World coverage of asbestos bans remains low.
Dr. RA Lemen

After bans enacted asbestos-related diseases will
begin to decrease after 10-20 years,
However,
They will never be eliminated entirely until all
asbestos is eliminated or under control.
With greater consumption of asbestos in
developing countries asbestos-related diseases
will increase if exposures are not eliminated.
In Conclusion -
Dr. RA Lemen

Quote From: Marty S. Kanarek, 2011.
Mesothelioma from chrysotile asbestos:
Update. AEP, 21(9): 688-699, September.
“Thus, it is reasonable to assume that the
total numbers of cases that are documented
Is just the tip of the iceberg
of a potential world-wide environmental
cancer epidemic of mesothelioma from asbestos,
including chrysotile asbestos”
Dr. RA Lemen

What must we do?
To make a world-wide
ban a reality --
Dr. RA Lemen

Dr. Richard Lemen: What you should know about asbestos

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