Welding Fume Exposure Assessment of Welders Working … · Welding Fume Exposure Assessment of Welders Working in Isolation ... SMAW, MIG. 3 Health Effects ... 12 SMAW/MS Work Process

Welding Fume Exposure Assessment of Welders Working in Isolation

Laurel Berman, Ph.D.

with Serap Erdal, Ph.D., Lorraine Conroy, Ph.D., John Franke, Ph.D., Ernesto Indacochea, Ph.D., Peter Scheff, Ph.D., and Daniel Tessier, Ph.D.,

all at University of Illinois at Chicago

American Industrial Hygiene Association Conference and Exposition

May 13-16, 2006Chicago, Illinois

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Introduction: Welding• Over ½ million workers

in the U.S. are involved with welding and related processes

• Fume is a complex mixture of metals, silicates, oxides– About 90% respirable,

< 1 µm aerodynamic diameter

– Exposures are complex: e.g., heavy metals, fine particulates, gases

• Focus: SMAW, MIG

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Health Effects, Regulatory LimitsExposure to welding fume has been associated with a variety of adverse health effects, including:

• Respiratory effects (MFF, bronchitis)• Cancer (Cr, Ni)• Effects on reproductive organs• Neurological effects – Manganism?

– Welding fume• ACGIH TLV-TWA is 3 mg/m3, respirable, 10 mg/m3 total• OSHA PEL (PNOC) is 5 mg/m3 respirable, 15 mg/m3

total • (NIOSH REL, PNOR is also 5 and 15 mg/m3, respirable

and total)

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Study Question/Objectives:

• What are the exposures of welders under isolated conditions?

• Challenge: – A population that works alone – isolation of

exposure • Solution:

– Artists/metal sculptors• Typically work alone• Use processes common to industry/production welding• Special population at risk (NORA)

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Methods: Personal Exposure, Respirable Fume and Fume Components

• Personal samples: breathing zone, respirable

• Cyclone samplers, 4.0 µm cut-point• 2.5 lpm, pumps• 37-mm Teflon filters• Wisconsin State Laboratory of Hygiene

(WSLH) for analysis– Filters pre and post-weighed by WSLH (robotic)– Gravimetric analysis– ICPMS analysis

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Methods: Subjects/Processes Monitored

• Artist A: SMAW/SS, E308H-16, 18 days• Artist B: MIG/MS, ER100S-1, 6 days• Artist C: SMAW/MS, E6011, 16 days• Typical workday: 4 hours, 8+ under deadline• Exposures to respirable and elemental

components measured under both field and laboratory conditions– Studio– Exposure chamber

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Artist A’s Studio Space: SMAW/SSPole barn, well-ventilated: box fan/door, large public art, 40 yrs exp.

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Exposures: fumes generated from welding, plasma cutting, grinding

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Artist B’s Studio Space: MIG/MSWithin large warehouse facility, dilution ventilation: dock doors/exits.

Large public art, 35 yrs exp.

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Exposures: fume from welding, cutting, grinding

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Artist C’s Studio Space: SMAW/MSOld industrial facility, now studios and business, 13X40 feet. Small,

“human” forms, private collections/exhibitions, 10 yrs exp.

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SMAW/MS Work Process

• Scavenged/found metals– Including painted

floor panels (Pb) • Two ventilation

conditions• Exposures were

from welding and cutting (no grinding)

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Personal Exposure Concentrations – Respirable Fume, Descriptive Statistics

0.880.180.762.03SD

3.190.752.31** (SuperMIG)

7.72Max

1.540.560.702.98Mean

0.610.360.210.54Min

C #2: SMAW/ MS Conc(mg/m3)

C #1: SMAW/ MS Conc(mg/m3)

B: MIG/MS Conc (mg/m3)

A: SMAW/ SS Conc(mg/m3)

Statist. Descrip-tor

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Personal Exposures to Respirable Particles

• SMAW/SS, Artist A: highest exposures, most variable (SD)– 8 of 18 near or over PEL (PNOC, resp.)

• MIG/MS, Artist B: exposures < PEL • SMAW/MS, Artist C:

– exposures < PEL (fan)– 3 near or > ½ PEL (no fan)

• All artists: not a full workshift– TWA: some zero exposure times unless

maximum production conditions

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Personal Exposure Concentrations: Elemental Composition

• ICPMS: 42 elements for the three processes• Restricted to metals > 0.1% of total metal

mass • Iron greatest component for all three fume

types (as expected)• SMAW/SS – 33% of fume metal• MIG/MS – 22% of fume metal• SMAW/MS – 22 –26% of fume metal

• Remainder: silicates, oxides

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Results –Elemental Fume Composition, Personal Samples

• Fe major component of all fume types – Cu, Mn, Ti also present in all fume types

• Day-to-day variability both gravimetric and elemental– Activity based

• Average elemental concentrations did not exceed individual metals TLVs – View use of TLVs with caution

• a mixture of metals vs. individual metals• fume component interactions• Samples were not full shift

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Results – Composition, Chamber Samples• Samples also exhibited

variability (not expected)– Controlled conditions – However, blanks were also

variable

• Chamber sample mean metal concentrations typically exceeded TLV for individual components– Mn– Cr, Ni (SS) – Fe (MS/6011)– Interpret with caution – only a

few minutes of welding, very intense

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Chamber Sample Fume Composition vs. Personal Sample Fume Composition

• Chamber and personal samples differed:

– Different metals

– Different % of total metal mass

– Different % of total fume mass

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Fume Composition: Field vs. Chamber Samples e.g. SMAW/SS

Studio SMAW/SS:12 Metals > 0.1% of Total Metal Mass

05

101520253035

Mg Mo Al Na Ca Cu Ti Ni Mn Cr K Fe

Metal

Perc

ent T

otal

Met

al

Mas

s (%

)

Fe: 32%, Cr:14%, Mn: 13%, Ti: 6%

Fe and Mn: 22%, Cr: 20%, Ti: 10%

Chamber SMAW/SS14 Metals Comprising > 0.1% of Total Metal Mass

0

10

20

30

Sn V Ca Cu Mg Zn Al Na Ni Ti K Cr Mn Fe

Metal%

Tot

al M

etal

Mas

s

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Fume Composition: Field vs. Chamber Samples e.g. MIG/MS

9 Metals Comprising > 0.1% of Total Metal Mass, Excluding Fe (65%)

05

1015202530

Sn Mo Mg Na Ni Cu Zn Mn

Metals

% T

otal

Met

al M

ass

Fe: 73%, Mn: 10%, Zn: 0.8%

Fe: 65%, Mn: 24%, Zn: 7%

Studio: 14 Metals Comprising > 0.1% of Total Metal Mass, Excluding Fe (73%)

0

10

20

30

As Sn Ti Mo Cr Mg Zn Cu Na Ni Ca K Mn

Metal

Perc

ent T

otal

M

etal

Mas

s

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Conclusions• Field activities are critical when assessing welding fume

exposures– e.g. plasma/oxy-cutting: vaporization of base metal– e.g. grinding: at least 30% respirable– e.g. arc time, 20 – 25%

• This means 2 h of 8 h day

• Field-based activities are critical to understanding real exposures– Laboratory data is useful but for “welding only”– Better if conditions can be matched

• e.g. # of electrodes, sampling time– Laboratory-based studies typically neglect these true

field conditions (arc time, grinding, cutting), leading to over-estimations of exposure

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Acknowledgements• The artists• NIOSH Training Grant

Number T42/CCT522954

• 2004 NIOSH Education Program in Occupational Safety and Health Pilot Project Research Grant

• The contents are solely the responsibility of the author(s) and do not necessarily represent the official views of NIOSH

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QUESTIONS?

Contact Information:Laurel Berman, Ph.D.Boelter and Yates, Inc.

[email protected]@gmail.com