We have been a pioneer in North America, providing welding fume extraction solutions since the 1980s. In this blog post, you will find the exposure limits in California for some of the most common hazardous metals and gases found in welding fume.

Fumes are formed when a metal is heated above its boiling point, and its vapors condense into very fine particles. Their size ranges from 0.005 to 20 µm, but most are smaller than 1 µm and may deposit throughout the respiratory system.

The fume composition depends on the material being welded, the electrode, the coatings, the flux, and the shielding gas, among other things. Air sampling is usually necessary to know which hazardous and regulated substances are in your working environment. But getting information on the composition of metals, gases, and consumables used in the welding process is usually a good start.

What particulates are potentially dangerous in welding fume?

Here is a list of some common dangerous metals and gases found in welding fume that will be covered on this page:

  • Aluminum
  • Antimony
  • Arsenic
  • Beryllium
  • Cadmium
  • Chromium
  • Cobalt
  • Copper
  • Iron oxide
  • Lead
  • Manganese (learn more about manganese in welding fumes)
  • Molybdenum
  • Nickel
  • Silver
  • Tin
  • Titanium dioxide
  • Vanadium
  • Zinc
  • Argon
  • Carbon Dioxide
  • Carbon Monoxide
  • Helium
  • Hydrogen Fluoride
  • Nitric Oxide
  • Nitrogen
  • Nitrogen Dioxide
  • Ozone
  • Phosgene

In California, the Division of Occupational Safety and Health (DOSH), better known as Cal/OSHA, is responsible for setting and enforcing exposure limits for air contaminants. For other US states, please read the article about welding fume regulations in the US.

This blog post will also introduce the recommendations of two major organizations influencing OSHA: the National Institute for Occupational Safety and Health (NIOSH) and the American Conference of Governmental Industrial Hygienists (ACGIH).

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Abbreviations used in the tables:

  • TWA: Time-Weighted Average for 8 hours
  • STEL: Short-Term Exposure Limit (maximum for 15 minutes, no more than four times per day, with at least 60 minutes in between)
  • C: Ceiling (must never be exceeded)
  • (i): Inhalable particles (smaller than 100 µm)
  • (r): Respirable particles (smaller than 4 µm)

Cal/OSHA – Permissible Exposure Limits for Welding Fume, Metals, and Gases

PELTWASTELC
Welding Fumes5mg/m3NoneNone
PELTWASTELC
Aluminum5mg/m3NoneNone
Antimony0.5mg/m3NoneNone
Arsenic, inorganic0.01mg/m3NoneNone
Arsenic, organic0.2mg/m3NoneNone
Beryllium0.2µg/m32µg/m30.025mg/m3
Cadmium5µg/m3NoneNone
Chromium (II) & (III)0.5mg/m3NoneNone
Chromium (VI)5µg/m3None0.1mg/m3
Cobalt0.02mg/m3NoneNone
Copper0.1mg/m3NoneNone
Iron5mg/m3NoneNone
Lead0.05mg/m3NoneNone
Manganese0.2mg/m33mg/m3None
Molybdenum3mg/m3(r)NoneNone
Nickel0.5mg/m3NoneNone
Silver0.01mg/m3NoneNone
Tin, organic0.1mg/m30.2mg/m3None
Tin oxide & inorganic2mg/m3NoneNone
Titanium*5mg/m3(r)NoneNone
Vanadium0.05mg/m3NoneNone
Zinc5mg/m3NoneNone
* Particulates not otherwise regulated
You can make sure these PELs are still applicable on OSHA’s website.
PELTWASTELC
Argon*NoneNoneNone
Carbon Dioxide5,000ppm30,000ppmNone
Carbon Monoxide25ppmNone200ppm
Helium*NoneNoneNone
Hydrogen Fluoride0.4ppm1ppmNone
Nitric Oxide25ppmNoneNone
Nitrogen*NoneNoneNone
Nitrogen DioxideNone1ppmNone
Ozone0.1ppm0.3ppmNone
Phosgene0.1ppmNoneNone
* A concentration limit is not included because available oxygen is the limiting factor.
You can make sure these PELs are still applicable on OSHA’s website.

NIOSH – Recommended Exposure Limits for Welding Fume, Metals, and Gases

RELTWASTELC
Welding FumesTBDTBDTBD
RELTWASTELC
Aluminum5mg/m3NoneNone
Antimony0.5mg/m3NoneNone
Arsenic, inorganicNoneNone2µg/m3
Arsenic, organicNoneNoneNone
BerylliumNoneNone0.5 µg/m3
CadmiumTBDTBDTBD
Chromium (II) & (III)0.5mg/m3NoneNone
Chromium (VI)1µg/m3NoneNone
Cobalt0.05mg/m3NoneNone
Copper0.1mg/m3NoneNone
Iron5mg/m3NoneNone
Lead0.05mg/m3NoneNone
Manganese1mg/m33mg/m3None
MolybdenumTBDTBDTBD
Nickel15µg/m3NoneNone
Silver0.01mg/m3NoneNone
Tin2mg/m3NoneNone
Titanium dioxideTBDTBDTBD
VanadiumNoneNone0.05mg/m3
Zinc oxide5mg/m310mg/m3None
You can make sure these PELs are still applicable on the CDC website.
RELTWASTELC
ArgonNoneNoneNone
Carbon Dioxide5,000ppm30,000ppmNone
Carbon Monoxide35ppmNone200ppm
HeliumNoneNoneNone
Hydrogen Fluoride3ppmNone6ppm
Nitric Oxide25ppmNoneNone
NitrogenNoneNoneNone
Nitrogen DioxideNone1ppmNone
OzoneNoneNone0.1ppm
Phosgene0.1ppmNone0.2ppm
You can make sure these PELs are still applicable on the CDC website.

ACGIH – Threshold Limit Values for Welding Fume, Metals, and Gases

TLVs are copyrighted by ACGIH and cannot be reproduced on other websites. You will find the links to the relevant pages on their website below.

ACGIH has not published a recommendation regarding welding fumes in general. Therefore, they fall under the Particulates Not Otherwise Regulated category. The ACGIH recommendation, in this case, is a TLV-TWA of 3mg/m3 for respirable particles and 10mg/m3 for inhalable particles.

* A concentration limit is not included because available oxygen is the limiting factor.

Health risks associated with breathing welding fumes

According to OSHA, the Centers for Disease Control and Prevention, the International Agency for Research on Cancer, and the CNESST (Canada), breathing welding fumes could cause the following health effects:

  • Eye, nose, and throat irritation
  • Dizziness and nausea
  • Breathing difficulties that could lead to suffocation or asphyxiation
  • Metal fume fever
  • Lung damage and various types of cancer
  • Stomach ulcers
  • Kidney damage
  • Nervous system damage
  • Manganism
  • Chest pain
  • Asthma
  • Bleedings
  • Dermatitis or eczema
  • Kidney disease
  • Bone and joint disorders
  • Siderosis (iron oxide in lung tissue after inhalation)
  • Stannosis (tin oxide in lung tissue after inhalation)
  • Anthracosis (poisoning after inhalation of carbon dust)
  • Berylliosis (poisoning after inhalation of beryllium dust)
  • Accumulation of fluid in the lungs

These are good reasons to protect welders, meet the standards, and even extract pollutants as efficiently as possible. Welding fume extractors will be the best way to do so.

3 Ways to Take a First Step Towards a Fume-Free Environment

1 – Attend Our Webinar

2 – Request our Compact Guide “30 Expert Tips for Eliminating Fume”

You will also receive information about regulations, success stories, tips to choose the right fume extractor.

3 – Contact Us

We would be pleased to help you protect your welders and comply with current standards. We travel everywhere in Canada and the United States for free demos.

1-800-922-2522
info@henlex.com