FIBERS AND CLEAVAGE FRAGMENTS

COMMENTS PERTINENT TO THE NIOSH DOCUMENT “ASBESTOS AND OTHER MINERAL FIBERS:A ROADMAP FOR

SCIENTIFIC RESEARCH”

GRAHAM WILLIAM GIBBS MSc PhD MRSC ROHSafety Health Environment International Consultants Corp.

Suite 101, 38, Athabasca Avenue,Devon, Alberta, Canada

GRAHAM W. GIBBSGRAHAM W. GIBBS

President Safety Health Environment International President Safety Health Environment International Consultants Corp.Consultants Corp.Adjunct Full Professor at University of Alberta.Adjunct Full Professor at University of Alberta.BScBSc Chemistry and Geology (London)Chemistry and Geology (London)MScMSc Geological Sciences (McGill)Geological Sciences (McGill)PhD Epidemiology (McGill)PhD Epidemiology (McGill)ROH Occupational HygieneROH Occupational HygieneMRSC (Member Royal Society of Chemistry).MRSC (Member Royal Society of Chemistry).

OCCUPATIONAL HYGIENE OCCUPATIONAL HYGIENE AND EPIDEMIOLOGYAND EPIDEMIOLOGY

RESEARCHRESEARCH-- ASBESTOSASBESTOS-- FIBERSFIBERS-- OCCUPATIONAL OCCUPATIONAL CANCERCANCER

-- OCCUPATIONAL OCCUPATIONAL DISEASESDISEASES

PURPOSE OF PRESENTATIONPURPOSE OF PRESENTATION

1.1. Share results of the study:Share results of the study:

““An evaluation of the Risks of Lung Cancer and An evaluation of the Risks of Lung Cancer and MesotheliomaMesothelioma from Exposure to Amphibole Cleavage from Exposure to Amphibole Cleavage FragmentsFragments””

by John F Gamble (IERF) and Graham W Gibbs by John F Gamble (IERF) and Graham W Gibbs (SHEI). (The paper is currently in press).(SHEI). (The paper is currently in press).

2.2. Comment on the Comment on the mesotheliomamesothelioma in Minnesota.in Minnesota.

APPROACHAPPROACH

Compare the lung cancer and Compare the lung cancer and mesotheliomamesotheliomaexperience of workers exposed to cleavage experience of workers exposed to cleavage fragments with experience of workers exposed fragments with experience of workers exposed to to asbestiformasbestiform equivalents.equivalents.

Workers Workers exposedexposed to amphibole cleavage to amphibole cleavage fragments.fragments.

Epidemiological studies have been conducted:Epidemiological studies have been conducted:

-- Gold mine South Dakota Gold mine South Dakota ((GruneriteGrunerite--cummingtonitecummingtonite exposure)exposure)

-- Taconite mines in Minnesota Taconite mines in Minnesota ((GruneriteGrunerite and and other nonother non--asbestiformasbestiform amphiboles)amphiboles)

Workers Workers exposedexposed to amphibole cleavage to amphibole cleavage fragments.fragments.

-- Talc mine in St Lawrence County, New York Talc mine in St Lawrence County, New York State (transition minerals, nonState (transition minerals, non--asbestiformasbestiformanthophylliteanthophyllite and and tremolitetremolite). ).

Workers exposed to Workers exposed to asbestiformasbestiformamphibolesamphiboles

AmositeAmosite asbestos mines, mills and asbestos mines, mills and manufacturing facilitiesmanufacturing facilities

Workers exposed to Workers exposed to asbestiformasbestiformamphibolesamphiboles

AnthophylliteAnthophyllite asbestos mines and millsasbestos mines and mills

AsbestiformAsbestiform TremoliteTremolite* in vermiculite mines * in vermiculite mines

**TremoliteTremolite term is used as this term has been used in term is used as this term has been used in medical literature concerning this facility to describe medical literature concerning this facility to describe amphibole fiber exposures. Amphiboles in the mine amphibole fiber exposures. Amphiboles in the mine appear to include appear to include tremolitetremolite, , winchitewinchite and and richteriterichterite..

RESULTSRESULTS--GRUNERITEGRUNERITE

C1 C2 C3 . .. UG AG , ' A1 A2 A3 A4

SMR

s (9

5% c

onfid

ence

inte

rval

s) fo

r lun

g ca

ncer

and

% fo

r mes

othe

liom

a

0

1

2

3

4

5

6

7

lung cancer SMRs% m eso (n cases/total deaths = PMR) No effect level for lung cancer (SMR=1)% m esotheliom a, asbestos cohortslung cancer SMRs, Asbestos cohorts

C1 = Steenland and Brown (1996)C2 = Higgins et al (1983)C3 = Cooper et al (1992)

UG, AG = underground and aboveground Hem atite (Lawler et al (1985)

A1 = Acheson et al (1984, am osite insulation m fgA2 = Seidm an et al (1986) am osite insulation factoryA3 = Lev in et al (1998) am osite insulation pipe m fg plantA4 = Sluis-Crem er et al (1992) chrysotile/am osite insulation

Nonasbestiformgrunerite

Hematite(no amphiboles)

Am osite (asbestiform grunerite)cohorts

Homestakegold mine

Taconite

Cumulative Exposure in fibers/cc-years

0 50 100 150 200 250 300

Stan

dard

ized

mor

talit

y ra

tio (S

MR

)

0

2

4

6

8

10

12

Hom estake Cohort (Steenland, 1995) Seidm an Am osite AsbestosNo increased risk (SMR=1.0)f/m l-yrs vs Hom estake pneum oconiosis

Am osite Insulationworkers

Seidman et al (1986)Hom estake Non-asbestiform grunerite

(Steenland and Brown, 1995)

lung cancer

pneumoconiosis

lung cancer

RESULTS RESULTS TREMOLITE/ANTHOPHYLLITETREMOLITE/ANTHOPHYLLITE

Cumulative Exposure (mg/m3-years)Original units in mg/m3-days converted to yrs dividing by 250 d/yr

0 10 20 30 40 50

Rel

ativ

e R

isk

(95%

con

fiden

ce in

terv

als)

0

1

2

3

4

5

6

7

8

9

10

11

12

Lung Cancer Other NMRD Fibrosis Increased risk >1.0, decreased risk <1.0

Lung Fibrosis

Other NMRD

Lung Cancer

FIGURE 3Exposure-response of lung cancer, other non-malignant respiratorydisease (other NMRD) and lung fibrosis by cumulative exposure (mg/m3-years)Honda et al (2002)

Cumulative Exposure = fibers/ml-years

0 100 200 300 400 500 600

Rel

ativ

e R

isk

(SM

R o

r OR

)

-1

0

1

2

3

4

5

6

7

8

9

10

lung cancer SMRs-SCpneumoconiosis regression-Libby Lung Cancer regression analysis-LibbyMesothelioma regression analysis-LibbyIncreased Risk >1 above line, reduced risk <1 bLC SMR by exposure category Libby 1986

Lung CancerLibby

Pneumoconiosis

Mesothelioma

lung cancerS.C

Cumulative Exposure (mg/m3-years)

0 200 400 600 800 1000

Odd

s R

atio

s

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

Lung Cancer NMRD regression pneumoconiosis regressionOR <1.0 = no effect

Lung Cancer

NMRD

Pneumoconiosis

ExposureExposure--response trends for lung cancerresponse trends for lung cancerNonNon--malignant respiratory disease (NMRD) and malignant respiratory disease (NMRD) and

Pneumoconiosis by cumulative exposure (mg/m3Pneumoconiosis by cumulative exposure (mg/m3--years)years)To Talc not containing amphibolesTo Talc not containing amphiboles

Among French/Austrian Talc WorkersAmong French/Austrian Talc WorkersWild et al (2002)Wild et al (2002)

Lung cancer and Lung cancer and mesotheliomamesothelioma mortality in workers exposed to mortality in workers exposed to Talc containing Talc containing nonasbestiformnonasbestiform amphiboles in New York and Norwayamphiboles in New York and Norway

(Honda et al, 2002; (Honda et al, 2002; WergelandWergeland et al (1990)et al (1990)Talc without amphiboles (Vermont, Italy, France/Austria)Talc without amphiboles (Vermont, Italy, France/Austria)SelevanSelevan et al (1979), et al (1979), CoggiolaCoggiola et al (2003), Wild et al, (2002)et al (2003), Wild et al, (2002)

andandVermiculite containing Vermiculite containing tremolitetremolite asbestos (McDonald et al (1986asbestos (McDonald et al (1986

Anthophyllite Asbestos (Karjalainen et al, 1994;Meurman et al, 1Anthophyllite Asbestos (Karjalainen et al, 1994;Meurman et al, 1994)994)

GTC Norway Vermont Italy FranceAustria S.C. MN Finland

SM

R (9

5% c

onfid

ence

inte

rval

) for

lung

can

cer

PM

R (%

) for

mes

othe

liom

a

0

1

2

3

4

5

Lung Cancer SMRs

PMRs for mesothelioma

Talc amphibole cleavage

fragments

Talcwithout amphiboles

Tremolite asbestosanthophyllite asbestos

COMPARISON GRUNERITE (ASBESTOS) (Mining SA, COMPARISON GRUNERITE (ASBESTOS) (Mining SA, Manufacturing UK, US, US)VS NONManufacturing UK, US, US)VS NON--ASBESTIFORM ASBESTIFORM

EXPERIENCE. (EXPERIENCE. (HomestakeHomestake, Reserve, Erie), Reserve, Erie)

PopulationPopulation No in cohortNo in cohort% Dead% Dead

No. No. MesoMeso%%

SMRSMR--LUNG LUNG CANCERCANCER

AsbestiformAsbestiformgruneritegrunerite ((AmositeAmosite))

9607 (18.7%)9607 (18.7%) 21/1796=1.2%21/1796=1.2% 224/81=2.77224/81=2.77

NonNon--AsbestiformAsbestiformgruneritegrunerite

12510 (23.2%)12510 (23.2%) 0 /2907 = 00 /2907 = 0 192/2119=0.91192/2119=0.91

Comparison NonComparison Non--AsbestiformAsbestiform GruneriteGrunerite ((SteenlandSteenland & Brown & Brown 1995) 1995) –– AsbestiformAsbestiform GruneriteGrunerite ((SeidmanSeidman et al 1986) (Assumes 1 et al 1986) (Assumes 1

MPPCF= 0.146 f/mlMPPCF= 0.146 f/ml

f/mlf/ml--yrsyrs

<4.8<4.8

<6<6

4.84.8--19.519.5

66--11.911.9

19.519.5--29.229.2

1212--24.924.9

>29.>29.

2525--44.944.9 5050--99.999.9 100100--149.9149.9

150150--249.0249.0 250+250+

SMRNSMRNonAsbonAsb

1.171.17 1.011.01 0.970.97 1.311.31

SMRAsSMRAsbb

2.642.64 4.154.15 4.424.42 4.424.42 7.147.14 6.046.04 9.099.09 11.711.7

MINNESOTA MINNESOTA --TACONITETACONITE

EXCESS OF MESOTHELIOMAEXCESS OF MESOTHELIOMALINKED TO MINING?LINKED TO MINING?

NEEDS: WELL CONDUCTEDNEEDS: WELL CONDUCTEDEPIDEMIOLOGICAL STUDY OFEPIDEMIOLOGICAL STUDY OFMESOTHELIOMA WITH APPROPRIATEMESOTHELIOMA WITH APPROPRIATECONTROLS AND TISSUECONTROLS AND TISSUEANALYSES.ANALYSES.

COMMENTS & THOUGHTSCOMMENTS & THOUGHTSThoracic fraction?Thoracic fraction?-- CautionCaution--EpidemiologyEpidemiology--Conversion?Conversion?-- Already the current Already the current fibrefibre counting ignores effect of counting ignores effect of diameters (diameters (EgEg: more : more amositeamosite fibers; Fewer fibers; Fewer crocidolitecrocidolitefibers seen). Validity of fiber exposure and risk fibers seen). Validity of fiber exposure and risk comparisons?comparisons?

Need method to distinguish cleavage fragments from Need method to distinguish cleavage fragments from real fibers.real fibers.-- Consider Aerosol spectrometer Consider Aerosol spectrometer -- TimbrellTimbrell-- Consider magnetic alignment Consider magnetic alignment –– TimbrellTimbrell-- Horizontal Horizontal eleutriationeleutriation –– separates diametersseparates diameters-- NanoNano--technology surface expertise?technology surface expertise?

GENERAL GENERAL COMMENT/SUGGESTIONCOMMENT/SUGGESTION

Workshops and think tanks on specific topics.Workshops and think tanks on specific topics.

What has changed? What has changed? –– levels of exposure and levels of exposure and technology.technology.