Welding-Hazards-AFSCME-fact-sheet.pdfVIP专享VIP免费原创优质

WELDINGHAZARDSWeldingjoinspiecesofmetalbytheuseofheat,pressure,orboth.Brazing,orsoldering,involvesafillermetaloralloy(acombinationofmetals)whichhasalowermeltingpointthanthemetalpiecestobejoined.Thefillermaterials(suchasleadandcadmium)canbeverytoxic.Metalcuttingisdonebyheatingthemetalwithaflameanddirectingastreamofpureoxygenalongthelinetobecut.Therearemorethan80differenttypesofweldingandassociatedprocesses.Someofthemostcommontypesofweldingare:arcwelding,whichincludes“stick,”orshieldedmetalarcwelding(SMAW),thegas-shieldedmethodsofmetalinertgas(MIG)andtungsteninertgas(TIG),plasmaarcwelding(PAW)andsubmergedarcwelding(SAW).Otherweldingprocessesmayuseoxy-acetylenegas,electricalcurrentlasers,electronbeams,friction,ultrasonicsound,chemicalreactions,heatfromfuelgasandrobots.HealthHazardsofWeldingGasesandFumesWelding“smoke”isamixtureofveryfineparticles(fumes)andgases.Manyofthesubstancesinweldingsmoke,suchaschromium,nickel,arsenic,asbestos,manganese,silica,beryllium,cadmium,nitrogenoxides,phosgene,acrolein,fluorinecompounds,carbonmonoxide,cobalt,copper,lead,ozone,seleniumandzinc,canbeextremelytoxic.Generally,weldingfumesandgasescomefrom:thebasematerialbeingweldedorthefillermaterialthatisused;coatingsandpaintsonthemetalbeingwelded,orcoatingscoveringtheelectrode;shieldinggasessuppliedfromcylinders;chemicalreactionswhichresultbytheactionofultravioletlightfromthearcandheat;processandconsumablesused;andcontaminantsintheair,forexamplevaporsfromcleanersanddegreasers.Thehealtheffectsofweldingexposuresaredifficulttolist,becausethefumesmaycontainsomanydifferentsubstancesthatareknowntobeharmful.Theindividualcomponentsofweldingsmokecanaffectanypartofthebody,includingthelungs,heart,kidneysandcentralnervoussystem.Welderswhosmokemaybeatgreaterriskofhealthimpairmentthanwelderswhodonotsmoke,althoughallweldersareatrisk.2Exposuretoweldingsmokemayhaveshort-termandlong-termhealtheffects.Theseeffectsaredescribedbelow:Short-Term(Acute)HealthEffectsExposuretometalfumes(suchaszinc,magnesium,copper,andcopperoxide)cancausemetalfumefever.Symptomsofmetalfumefevermayoccur4to12hoursafterexposure,andincludechills,thirst,fever,muscleache,chestsoreness,coughing,wheezing,fatigue,nauseaandametallictasteinthemouth.Weldingsmokecanalsoirritatetheeyes,nose,chest,andrespiratorytract,andcausecoughing,wheezing,shortnessofbreath,bronchitis,pulmonaryedema(fluidinthelungs)andpneumonitis(inflammationofthelungs).Gastrointestinaleffects,suchasnausea,lossofappetite,vomiting,cramps,andslowdigestion,havealsobeenassociatedwithwelding.Somecomponentsofweldingfume,forexamplecadmium,canbefatalinashorttime.Gasesgivenoffbytheweldingprocesscanalsobeextremelydangerous.Forexample,ultravioletradiationgivenoffbyweldingreactswithoxygenandnitrogenintheairtoformozoneandnitrogenoxides.Thesegasesaredeadlyathighdosesandcanalsocauseirritationofthenoseandthroatandseriouslungdisease.Ultravioletraysgivenoffbyweldingcanreactwithchlorinatedhydrocarbonsolvents,suchas1,1,1-trichloroethane,trichloroethylene,methylenechloride,andperchloroethylene,toformphosgenegas.Evenaverysmallamountofphosgenemaybedeadly,althoughearlysymptomsofexposure--dizziness,chills,andcough--usuallytake5or6hourstoappear.Arcweldingshouldneverbeperformedwithin200feetofdegreasingequipmentorsolvents.Long-Term(Chronic)HealthEffectsStudiesofwelders,flamecutters,andburnershaves...