Alterna(vestoMethylisothiazolinoneandChloromethylisothiazolinonein
LeatherTanningTomLewandowski,Ph.D.,DABT,ERT,ATS
SaraPachecoShubin,Ph.D.JoelM.Cohen,Ph.D.
2ndInternaConalSymposiumonAlternaCvesAssessmentNovember1,2018
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LeatherTanningProcess
• LOTSofchemicalsareusedinleatherproduc(on
• Chromates(80-95%ofproducCon),vegetabletanninsorglutaraldehyde
• Fatliquoringagents• Dyes,pigmentsandrelatedchemicals
• Adhesives• Finishes• AnCmicrobials
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LeatherPreserva(vesandSkinSensi(za(on
• Isothiazolones• Widelyusedinleatherandother
consumerproducts• Somearehighlypotentskin
sensiCzers/allergens• Methyisothiazolone(MI)/
chloromethylisothiazolone(MCI)usedincombinaConasKathonCG
• IncreasinglybeingrestrictedincosmeCcsandotherproducts
• SensiCzaConexposurelimitforMCIis1.9mcg/cm2skinsurfacearea methylisothiazolinone(MI)
methylchloroisothiazolinone(MCI)
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CaseStudy
• CompanyproducesconsumerproductsofwhichleatherwriststrapsareoneproductopCon• Newproductmodelsarerigorously
testedforchemicalleachingpriortorelease
• TesCngrevealsMI/MCIpresentinextractsofleatherproducts• Mosthaveacceptablylow
concentraConsbutafewfailandmustberedesigned(atsubstanCalCme&cost)
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CaseStudy
• Ques(on:AretherealternaCvestoMI/MCIinleatherthatwecanproposetooursuppliers?
• Solu(on:ConductanIC2Stage1AAtoseewhatopConsarepossible
• Goal:BeabletohaveaninformedconversaConwithsuppliersaboutpossibleopCons
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Ini(alAAQues(ons
• Canthechemicaljustbeeliminated?• No.Duetothebiologicalnature
ofleather,someanCmicrobialisneeded
• Canthecompanyjustavoidusingleather?• No.Customersareaskingfor
leatherproducts.
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Stage1IC2AAProcess
• Highlevelreviewtoseeifdataareavailabletosupportamorein-depthAA
• Limitedtodatathatarereadilyavailable(nonewresearch,noproprietarydata)
• Modules:Hazard,Availability,Exposure,Performance,Cost
• Scope:LimitedtoalternaCvesactuallyinthemarketplace
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Process
• IdenCfyPossibleBiocides• Beingused/havebeensuggestedforuseinleatherproducConorrelatedprocesses• Manufacturerwebsites• Governmentreports• JournalarCcles
• QualitaCvescreenforHazard,ExposurePotenCal,Performance,AvailabilityandCost• Pharosforhazard,EpiSuiteforPhys/
Chemdata,on-linesearchesforperformance,availabilityandcost
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BiocidesWithDocumentedUseinLeatherTanningorRelatedMaterialsorProcesses
• Sodium-dimethyldithiocarbamate• Potassium-dimethyldithiocarbamate• Phenoxyethanol• 2(Thiocyanomethylthio)benzothiazole(TCMBT);alsoreferredtoasTCMTB
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HazardsofAlterna(ves(viaPharos)
CommonChemicalName SkinSensi(za(on Carcinogenic Mutagenic Repro/Developmental Ecological Other
Compo
undsofC
oncern
Methylisothiazolinone(CAS2682-20-4)
SkinsensiCzer.POD=16.5μg/cm2 Notflagged Notflagged Notflagged Yes(GHSVery
Toxic)
EyeIrritaCon(NZ,A)SkinIrritaCon(A)Endocrine(TEDEX)AcuteInhalaCon(A)
RespiratoryIrritaCon(EU)
Methylchloroisothiazolinone(26172-55-4)
SkinsensiCzer.POD=1.9μg/cm2 Notflagged Notflagged Notflagged Yes(GHSVery
Toxic)
AcuteInhalaCon(A)EyeIrritaCon(NZ,A)SkinIrritaCon(A)
PossibleAlte
rna(
ves
Sodium-dimethyldithiocarbamate
(128-04-1)
PossiblesensiCzer(structuralalert).esCmatedPOD=
250μg/cm2
Notflagged Yes(GHSCat2)
Yes(GHSCat2,Prop65) Yes(GHSCat1)
STOTSingle(J)AcuteOral(NZ)
SkinIrritaCon(J)21564-17-0
Potassium-dimethyldithiocarbamate
(128-03-0)
PossiblesensiCzer(structuralalert).esCmatedPOD=
250μg/cm2
Notflagged Yes(GHSCat2)
Yes(GHSCat2,Prop65)
Yes(GHSVeryToxic) Nootherhazardsflagged
Phenoxyethanol(122-99-6) Non-sensiCzer Notflagged Notflagged Yes(GHSCat2
but>375mg/kg)Yes(GHSHarmful)
AcuteOral(EU)EyeIrritaCon(EU)STOTSingle(J)
TCMBT(21564-17-0)
SkinsensiCzer.POD=25,000μg/
cm2Notflagged Notflagged Yes(GHSCat2
but>125mg/kg)Yes(GHSVery
Toxic)
Endocrine(TEDEX)AcuteInhalaCon(EU)EyeIrritaCon(EU)SkinIrritaCon(EU)STOTSingle(NZ)
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ResultsofStage1AA
CommonChemicalName Performance Hazard Availability Compara(veExposure
Compara(veCostperton
Compo
undsof
Concern
Methylisothiazolinone(CAS2682-20-4) Demonstrateduse SkinsensiCzer,not
reprotoxic,aquaCctoxicity Readilyavailable
ExisCngchemicals ExisCngchemicalsMethylchloro
isothiazolinone(26172-55-4)
Demonstrateduse SkinsensiCzer,notreprotoxic,aquaCctoxicity Readilyavailable
PossibleAlte
rna(
ves
Sodiumdimethyldithiocarbamate
(128-04-1)
Usedinleatherprocess,abilityto
replaceisothiazolonesuncertain
PossibleskinsensiCzer,mutagenic,Prop65Reprohazard,aquaCctoxicity
Readilyavailable LessvolaCle,morehydrophillic Less
Potassiumdimethyldithiocarbamate
(128-03-0)
Usedinleatherprocess,abilityto
replaceisothiazolonesuncertain
PossibleskinsensiCzer,mutagenic,Prop65Reprohazard,aquaCctoxicity
ReadilyavailableLessvolaCle,more
hydrophillic
similar
Phenoxyethanol(122-99-6)
UsedintexCleprocessing,replacing
isothiazolonesinsomeconsumer
products
NotsensiCzing,reproathighconcentraCons(>300mg/kg),
lowestaquaCctoxicityReadilyavailable
SimilarvolaClity,morehydrophobic
similar
TCMBT(21564-17-0)
Marketedforuseinleatherprocess,abilitytoreplaceMI/MCIunknown
NotsensiCzing,reproathighconcentraCons,endocrineacCve,aquaCctoxicity
Readilyavailable LessvolaCle,morehydrophobic
Substan/allyhigher
Note:Costdataarehighlyuncertainandrepresentcostofbulkmaterial,notcostaccounCngfordifferentanCmicrobialpotency(nodataavailable)
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KeyFindings
• MI/CMIactuallyhavesomebenefitsovermostalternaCves• PhenoxyethanoloffersthebesttradeoffbetweensensiCzaConandotherhealthhazards• Notclearitcouldbeusedinleathertanning
• TCMBTisnonsensiCzingandisbeingmarketedforuseinleatherproducCon• CostcouldbesubstanCallyhigher,dependingonrelaCvepotency• ReportedendocrineacCvityneedstobeevaluatedmoreclosely
• Companyshouldcontactsuppliers,getinputandexplorepossibiliCes
• Dependingonsupplierinput,conducta2ndStageAA
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Limita(ons
• Thereareotherchemicalsofconcerninleather(chromiumVI,acrylateorformaldehydebasedadhesives)–arewetargeCngthekeyconcern?
• Availablecostdataareofextremelypoorquality,specificpricesdependonvolumeandcontracCng• WhatreallymasersiscostforequivalentanCmicrobialeffectfor
whichdatacouldnotbelocated
• DifficultforasmallpurchasertoputpressureonsupplierstoresearchnewopCons
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