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Welding Fumes: Health Hazards and MSHA Regulations

Understand welding fumes, their composition, toxicity, and regulations. Learn about sampling methods, controls, and potential health risks associated with exposure to welding fumes. Respirable particles size comparison provided.

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Welding Fumes: Health Hazards and MSHA Regulations

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  1. Welding Fumes

  2. Welding Fumes • What Are Welding Fumes ? • Health Hazards • MSHA Regulations • Sampling Methods • Controls

  3. Welding Fumes • What Are Welding Fumes ? • Health Hazards • MSHA Regulations • Sampling Methods • Controls

  4. What Are Welding Fumes ? • Welding Causes Solid Metal To Vaporize • As Vaporized Metal Cools, It Condenses To Reform As Solid Particles - FUME • Fumes Are Very Small Particles - - Usually Much Smaller Than Dust • Dust Usually Larger Than 1 Micron • Fumes Can Be As Small As 1/1,000 Micron • Unless Captured And Removed, Fumes Remain Suspended In Air Indefinitely

  5. How Big Is A Micron ?

  6. How Big Is A Micron ? Head of Pin 1/32 Inch

  7. How Big Is A Micron ? 20 Microns Head of Pin 1/32 Inch

  8. Size Comparison of Small Particles m Washed Foundry Sand 200 to 2,000 Plant Spores 10.0 to 40 Red Blood Cells 7 Cement Dust 1.0 to 10 Bacteria 1/10 to 10 Tobacco Smoke 1/100 to 1/2 Metal Fumes 1/1,000 to 1.0

  9. Composition of Welding Fumes • Composition Varies Depending On: • Material Being Welded • Welding Process, Rod, Electrode Type • Obtain MSDS From Manufacturer • Typical Welding Fume Constituents: • Aluminum, Cadmium, Chromium, Iron, Moly • Cobalt, Copper, Zinc, Manganese, Tin, Lead • Nickel, Arsenic, Mercury, Vanadium, • Beryllium, Magnesium, Titanium, • May Be Metal or Oxide

  10. Welding Fumes • What Are Welding Fumes ? • Health Hazards • MSHA Regulations • Sampling Methods • Controls

  11. Exposure Primarily By Inhalation

  12. Exposure Primarily By Inhalation Fumes Are 100% Respirable

  13. Exposure Primarily By Inhalation Fumes Are 100% Respirable What Does “Respirable” Mean ?

  14. Exposure Primarily By Inhalation Fumes Are 100% Respirable What Does “Respirable” Mean ?

  15. Welding Fume Toxicity • Acute Toxicity • Exposure To High Concentration Over Relatively Short Time • Symptoms Appear Relatively Quickly After Exposure • Chronic Toxicity • Exposure To Lower Concentration Over Long Time (Months, Years) • Symptoms Appear Long After Initial Exposure

  16. Welding Fume Toxicity Kidney Nervous Liver GI Lung Aluminum X X Beryllium X Cadmium X X X X Chromium X X X X Cobalt X X X Copper X X Iron X X X X Lead X X X Manganese X X Nickel X X Zinc X X

  17. Welding Fume Toxicity • Exposure Usually Involves More Than One Metal • Toxic Effects May Be Additive • Examples • Blood - Manganese and Lead • CNS - Manganese and Lead • Kidney - Lead and Cadmium • Respiratory System - Magnesium, Manganese, Copper, and Zinc

  18. Welding Fume Toxicity • Metal Fume Fever • Symptoms Are Fever, Chills, Shaking • Symptoms Appear 4-12 Hrs After Exp. • Recovery Usually Within 1 Day • Usually Associated With Brief High Inhalation Exposure To Zinc, But Magnesium & Copper Also May Cause • Daily Exposure May Confer Immunity • Symptoms May Return If Exposure Interrupted (3-Day Weekend)

  19. Welding Fume Toxicity • Welding Fumes Can Cause Cancer • Arsenic (Lung, Lymphatic) • Beryllium (Lung) • Cadmium (Prostatic and Lung) • Chromium (Lung) • Nickel (Lung) • Welders May Also Be Exposed To: • Silica, Asbestos, Ozone • Thermal Decomposition of Paint, Flux, Electrode Coatings (CO, CO2, NO, NO2, HCN, COCl2, Fluoride Gases, Smoke, Etc.)

  20. Welding Fumes • What Are Welding Fumes ? • Health Hazards • MSHA Regulations • Sampling Methods • Controls

  21. MSHA Regulations § 56/57.5001 Establishes Exposure Limits For Airborne Contaminants • TWA8 And Ceiling Limits Listed In 1973 ACGIH Booklet of Threshold Limit Values (TLV’s) • TWA8 Time Weighted Average For 8 Hrs • Ceiling Limits Cannot Be Exceeded For Any Length Of Time • ACGIH 1973 TLV Booklet References 1968 “PA Rules” For Short Term Limits

  22. Exposure Limits For Common Welding Fumes TWA8 Short Term Beryllium 2.0 g/m3 25.0 g/m3 Magnesium Oxide 10.0 mg/m3 20.0 mg/m3 Vanadium 50.0 g/m3 50.0 g/m3 Chromium 1.0 mg/m3 3.0 mg/m3 Manganese (C) 5.0 mg/m3 5.0 mg/m3 Nickel 1.0 mg/m3 3.0 mg/m3 Cobalt 100.0 g/m3 500.0 g/m3 Zinc Oxide 5.0 mg/m3 10.0 mg/m3

  23. Milligrams or Micrograms Per Cubic Meter of Air mg or g 1 meter 1 meter 1 meter 1 milligram = 1/1,000 gram = 35/1,000,000 oz 1 microgram = 1/1,000,000 gram = 35/1,000,000,000 oz

  24. How Much is 100 g/m3 ? 100 g/m3 = 0.1 ounce per 1,000,000 ft3

  25. MSHA Regulations §56/57.5002Dust, Gas, Mist, And Fume Surveys Shall Be Conducted As Frequently As Necessary To Determine The Adequacy Of Control Measures §56/57.5005Control of Harmful Airborne Contaminants Shall Be, Insofar As Feasible, By Engineering Controls • Respirators Permitted Under Certain Circumstances

  26. MSHA Regulations Part 46 and Part 48 Training §56/57.14213(b) All Welding Operations Shall Be Well Ventilated §56/57.20011Areas Where Health or Safety Hazards Exist That Are Not Immediately Obvious Shall Be Barricaded Or Warning Signs Posted

  27. Welding Fumes • What Are Welding Fumes ? • Health Hazards • MSHA Regulations • Sampling Methods • Controls

  28. Sampling Methods • For Compliance With §56/57.5001 And §56/57.5002 • Full Shift Or Short Term

  29. Sampling Methods • For Compliance With §56/57.5001 And §56/57.5002 • Full Shift Or Short Term • Sample Pump, Pump Calibrator, Filters

  30. Sampling Methods • For Compliance With §56/57.5001 And §56/57.5002 • Full Shift Or Short Term • Sample Pump, Pump Calibrator, Filters • Place Filter In Breathing Zone Under Hood

  31. Sampling Methods • For Compliance With §56/57.5001 And §56/57.5002 • Full Shift Or Short Term • Sample Pump, Pump Calibrator, Filters • Place Filter In Breathing Zone Under Hood • Pump Draws Air Over Filter; Contaminants Captured On Filter

  32. Sampling Methods • Analytic Lab Determines Weights Of Individual Contaminants On Filter • Weights Converted To Concentrations

  33. Sampling Methods • Analytic Lab Determines Weights Of Individual Contaminants On Filter • Weights Converted To Concentrations weight of contaminant volume of air

  34. Sampling Methods • Analytic Lab Determines Weights Of Individual Contaminants On Filter • Weights Converted To Concentrations weight of contaminant mg or g volume of air m3

  35. Sampling Methods • Analytic Lab Determines Weights Of Individual Contaminants On Filter • Weights Converted To Concentrations weight of contaminant mg or g volume of air m3 • Measured Concentration Compared To Established Exposure Limit

  36. Sampling Methods • Analytic Lab Determines Weights Of Individual Contaminants On Filter • Weights Converted To Concentrations weight of contaminant mg or g volume of air m3 • Measured Concentration Compared To Established Exposure Limit • Measured Less Than Limit - - No Action Req’d

  37. Sampling Methods • Analytic Lab Determines Weights Of Individual Contaminants On Filter • Weights Converted To Concentrations weight of contaminant mg or g volume of air m3 • Measured Concentration Compared To Established Exposure Limit • Measured Less Than Limit - - No Action Req’d • Measured Over Limit - - Implement Controls

  38. Welding Fumes • What Are Welding Fumes ? • Health Hazards • MSHA Regulations • Sampling Methods • Controls

  39. Controls (§56/57.5005) • Feasible Engineering Controls • Personal Protective Equipment (PPE) • PPE Allowed As Means Of Compliance Only In Limited Situations • Where Feasible Engineering Controls Do Not Exist • While Installing Engr. Controls • Occasional Entry Into Hazardous Atmosphere For Maintenance

  40. Engineering Controls • General Ventilation • Natural or Mechanically Induced (Fans) Airflow Over Work Area That Dilutes and Carries Away Contaminants • Local Exhaust Ventilation • Captures and Removes Airborne Contaminants Before They Escape Into Workplace Air • Local Exhaust Always Preferred For Toxic Airborne Contaminants

  41. General Ventilation • Outdoors - Wind • Indoors • Open Shop Doors/Windows • What Blows In, Must Blow Out • Fans • Fixed - Roof, Walls, Windows • Portable • Blow Fresh Air Into Work Area, But Don’t Blow Fumes Into Welder’s Breathing Zone • Push-Pull Fan Arrangements • Need Provision For “Make Up” Air

  42. Local Exhaust Ventilation • Capture Hood & Fixed Duct System

  43. Local Exhaust Ventilation • Portable “Fume Eliminator”

  44. Local Exhaust Ventilation • Down Draft Table

  45. Local Exhaust Ventilation • System Must Have Adequate Air Velocity To Draw In Fume Particles • Minimum Capture Velocity 100 ft/min • Better To Design For 200 ft/min • May Need Provision For “Make Up” Air • 10” Round Duct Drawing 200 ft/min • Air Volume Removed From Work Area Is 110 cfm

  46. Local Exhaust Ventilation • Must Position Hood Correctly • Air Velocity Drops Rapidly With Distance Away From Hood Opening

  47. Local Exhaust Ventilation • Must Position Hood Correctly • Air Velocity Drops Rapidly With Distance Away From Hood Opening Hood Opening 10 inches Airflow 10“  200 120 60 15 Air Velocity (ft/min)

  48. 1350 fpm 100 fpm

  49. Respiratory Protection • Air Purifying Or Supplied Air • May Be Integral With Welding Hood • Respirator Use Must Include Implementation of Respiratory Protection Program (See ANSI Z88.2-1969) • Written Procedures on Selection and Use • Respirator Training and Fit Testing • Respirator Inspection, Cleaning, Storage • Workplace Surveillance • Medical Evaluation Recommended

  50. Welder’s Powered Air Purifying Respirator (PAPR) Half-Mask Cartridge Respirator Supplied-Air Respirator

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