Air Monitoring Applications - Welding

Other Contaminants

Paint & Coating Residues
Isocyanates
Solvents
Phosgene
Fluorides
Arsenic
Asbestos
References
Welding Processes main page
Air Sampling Media by Regulatory Method
Method Contaminants of Interest Sampling Media
OSHA
OSHA 42 Diisocyanates Filter – Glass Fiber Filter Coated w/1-2PP (20811/20812-U)
New! Dry Sampler – ASSET EZ4-NCO Dry Sampler (5027-U/5028-U)
OSHA 47 Methylene Bisphenyl Isocyanate (MDI) Filter – Glass Fiber Filter Coated w/1-2PP (20811/20812-U)
New! Dry Sampler – ASSET EZ4-NCO Dry Sampler (5027-U/5028-U)
OSHA 61 Phosgene Sorbent Tube – 2-HMP on XAD-2 (20231)
OSHA 1006 Arsenic, Cadmium, Cobalt, Copper, Lead & Nickel Passive Sampling-radiello Aldehydes-(RAD165) / DSD-DNPH (28221-U)
OSHA ID 105  Inorganic Arsenic in Workplace Atmospheres Filter – MCE filter + support pad c/w Na2CO3 (Custom-Inquire)
OSHA ID 110 Fluoride (F- and HF) in Workplace Atmospheres Filter – MCE filter + support pad c/w Na2CO3 (Custom-Inquire)
OSHA ID 160 Asbestos in Air Filter – MCE (23380-U)
NIOSH
NIOSH 5521 Isocyanates Impinger (20270-U)
New! Dry Sampler – ASSET EZ4-NCO Dry Sampler (5027-U/5028-U)
NIOSH 5522 Isocyanates Impinger (20270-U)
New! Dry Sampler – ASSET EZ4-NCO Dry Sampler (5027-U/5028-U)
NIOSH 7400 Asbestos Fibers by PCM Filter – MCE (23380-U)
NIOSH 7402 Asbestos Fibers by TEM Filter – MCE (23380-U)
NIOSH 7900 Arsenic and Compounds, as Arsenic (except AsH3 & As2O3) Filter – MCE filter + support pad c/w Na2CO3 (Custom-Inquire)

Paint & Coating Residues

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In welding operations, the worker often welds metals that have been painted or coated to prevent the surface from oxidation or other means of deterioration. When high heat is applied to these coated surfaces, volatile compounds and gases are emitted which are often hazardous. For more information, please visit our Paints and Coatings section.

 


Isocyanates

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See information on Isocyanates under our Paints & Coatings section.

 


Solvents

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See information on Solvents under our Paints & Coatings section.

 


Phosgene (Carbonyl Chloride)

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Before welding metal surfaces, the worker often cleans or degreases the surface with hydrocarbon solvents which may contain compounds such as trichloroethylene, 1,1,1-trichloroethane (TCE), methylene chloride, and perchloroethylene (PCE). The vapors of these solvents are a concern in welding because heat and ultraviolet radiation from the arc will decompose the vapors and form highly toxic and irritating phosgene gas. Solvents used for degreasing purposes should be stored more than 200 feet from a welding arc. The odor of phosgene is recognized most often as the smell of fresh cut hay. Even a very small amount may be deadly, although early symptoms of exposure such as dizziness, chills, and cough, usually take 5 or 6 hours to appear.

 

Exposure Limits
Agency Exposure Limit
OSHA (PEL) for General Industry: 0.1 ppm, 0.4 mg/m³ TWA
for Maritime: 0.1 ppm, 0.4 mg/m³ TWA
ACGIH (TLV) 0.1 ppm, 0.4 mg/m³ TWA
NIOSH (REL) 0.1 ppm, 0.4 mg/m³ TWA; 0.2 ppm, 0.8 mg/m³ Ceiling (15 Minutes)
NIOSH (IDLH) 2 ppm
(TWA=Time-weighted average; TLV=Threshold Limit Value; PEL=Personal Exposure Limit, REL=Recommended Exposure Limit; IDLH=Immediately Dangerous to Life and Health concentration)

 


Fluorides

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In the process of arc welding, a welding electrode is used to fuse two metals together by conducting the current through the metal pieces. A type of welding known as flux-welding is employed to protect and clean the surface of the material and to prevent oxidation of base and filler materials. The flux may contain compounds with fluorides. Exposure to gaseous fluorides at low levels may irritate the eyes, nose and throat. In high concentrations, it may result in irritation of the pulmonary system leading to pulmonary edema.

 

Exposure Limits
Agency Exposure Limit
OSHA (PEL) for General Industry: 3 ppm, 2.5 mg/m³ TWA
for Maritime: 3 ppm, 2.5 mg/m³ TWA
(TWA=Time-weighted average; PEL=Personal Exposure Limit

 


Arsenic

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Arsenic exposure in welding processes often occurs when welding ores contain the compound as a by-product (along with other elements such as copper, lead, cobalt, and gold). Heat based applications involving welding, smelting and refining of these ores can produce arsenic fumes. It is also found in alloys in combination with lead and copper in batteries, bearings, electrotype metal, ammunition, automobile body solder, and in corrosion resistance materials. The highly purified metal is useful in semiconductor applications. It is a known carcinogen.

Exposure Limits
Agency Exposure Limit
OSHA (PEL) for General Industry: Cancer Hazard 29 CFR 1910.1018 -- 0.01 mg/m³ TWA; 0.005 mg/m³ Action Level; NOTE: This section applies to all occupational exposures to inorganic arsenic except employee exposures in agriculture or resulting from pesticide application, the treatment of wood with preservatives or the utilization of arsenically preserved wood.
for Construction Industry:
29 CFR 1926.1118 requirements identical to 1910.1018.
for Maritime: 29 CFR 1926.1118 requirements identical to 1910.1018.
ACGIH (TLV) 0.01 ppm, 0.4 mg/m³ TWA; Appendix A1 - Confirmed Human Carcinogen; BEI
NIOSH (REL) 0.002 mg/m³ Ceiling (15 Minutes); Appendix A - NIOSH Potential Occupational Carcinogens
NIOSH (IDLH) 5 mg As/m³
National Toxicology Program (NTP) carcinogenic classification: Known to be a Human Carcinogen [149 KB, PDF]
International Agency for Research on Cancer (IARC) carcinogenic classification: Group 1, carcinogenic to humans - Arsenic in drinking-water [58 KB, Vol. 84, PDF] and Arsenic and Arsenic Compounds [523 KB, Suppl. 7, PDF and 28 KB, Vol. 23, PDF]
(TWA=Time-weighted average; TLV=Threshold Limit Value; PEL=Personal Exposure Limit, REL=Recommended Exposure Limit, BEI=Biological Exposure Indices ; IDLH=Immediately Dangerous to Life and Health concentration)

 


Asbestos

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Asbestos was widely used in manufacturing of numerous items prior to the 1980’s but has since been eradicated from many manufacturing processes. Welders in particular were exposed to high levels of asbestos due to the coating of the rods and other materials with compounds containing up to 15 percent asbestos. Asbestos exposure causes a lung cancer known as mesothelioma which affects the lung tissue. Although asbestos has been removed from most materials, workers who previously welded items containing asbestos 20-30 years ago are still at risk because it develops over many years.

Exposure Limits
Agency Exposure Limit
OSHA (PEL) for General Industry: 0.1 fiber/cc TWA; 1.0 fiber/cc (Excursion Level-30 min)
for Construction Industry:
0.1 fiber/cc TWA; 1.0 fiber/cc (Excursion Level-30 min)
for Maritime: 0.1 fiber/cc TWA; 1.0 fiber/cc (Excursion Level-30 min)
ACGIH (TLV) 0.2 crocidolite; 0.5 amosite; 2 chrysotile and other asbestos fibers/cc; carcinogen
NIOSH (REL) 0.1 fiber (>5 µm long)/400 L; carcinogen
(TWA=Time-weighted average; TLV=Threshold Limit Value; PEL=Personal Exposure Limit, REL=Recommended Exposure Limit; IDLH=Immediately Dangerous to Life and Health concentration)

 



References back to top
OSHA Safety & Health Topics: Welding, Cutting, Brazing
OSHA Standards: Hexavalent Chromium
ASTDR – ToxFAQs™: Phosgene
OSHA Safety and Health Topics – Arsenic
ASTDR – ToxFAQs™: Arsenic
OSHA Fact Sheet – Asbestos (PDF)
OSHA Safety and Health Topics – Asbestos