Welding Fume Regulations and Exposure Limits in the US

Last updated in June 2024

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 the US 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 the US, the Occupational Safety and Health Administration (OSHA) is responsible for setting and enforcing exposure limits for air contaminants. For California, please read the specific article where you will find the Cal/OSHA welding fume standards.

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)

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

PEL	TWA	STEL	C
Welding Fumes*	5mg/m3(r) 15mg/m3(t)	None	None

PEL	TWA	STEL	C
Aluminum	5mg/m3(r) 15mg/m3(t)	None	None
Antimony	0.5mg/m3	None	None
Arsenic, organic	0.5mg/m3	None	None
Beryllium	0.2µg/m3	2µg/m3	None
Cadmium	5µg/m3	None	None
Chromium (II) & (III)	0.5mg/m3	None	None
Chromium (VI)	5µg/m3	None	None
Cobalt	0.1mg/m3	None	None
Copper	0.1mg/m3	None	None
Iron oxide	10mg/m3	None	None
Lead	50µg/m3*	None	None
Manganese	None	None	5mg/m3
Molybdenum	5mg/m3	None	None
Nickel	1mg/m3	None	None
Silver	0.01mg/m3	None	None
Tin, inorganic	2mg/m3	None	None
Tin, organic	0.1mg/m3	None	None
Titanium dioxide	15mg/m3	None	None
Vanadium	None	None	0.1mg/m3
Zinc	5mg/m3	None	None

PEL	TWA	STEL	C
Argon*	None	None	None
Carbon Dioxide	5,000ppm	None	None
Carbon Monoxide	50ppm	None	None
Helium*	None	None	None
Hydrogen Fluoride	3ppm	None	None
Nitric Oxide	25ppm	None	None
Nitrogen*	None	None	None
Nitrogen Dioxide	None	None	5ppm
Ozone	0.1ppm	None	None
Phosgene	0.1ppm	None	None

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

REL	TWA	STEL	C
Welding Fumes	TBD	TBD	TBD

REL	TWA	STEL	C
Aluminum	5mg/m3	None	None
Antimony	0.5mg/m3	None	None
Arsenic, inorganic	None	None	2µg/m3
Arsenic, organic	None	None	None
Beryllium	None	None	0.5 µg/m3
Cadmium	As low as possible	TBD	As low as possible
Chromium (II) & (III)	0.5mg/m3	None	None
Chromium (VI)	1µg/m3	None	None
Cobalt	0.05mg/m3	None	None
Copper	0.1mg/m3	None	None
Iron	5mg/m3	None	None
Lead	0.05mg/m3	None	None
Manganese	1mg/m3	3mg/m3	None
Molybdenum	5mg/m3*	None	None
Nickel	15µg/m3	None	None
Silver	0.01mg/m3	None	None
Tin	2mg/m3	None	None
Titanium dioxide	As low as possible	As low as possible	As low as possible
Vanadium	None	None	0.05mg/m3
Zinc oxide	5mg/m3	10mg/m3	None

REL	TWA	STEL	C
Argon	None	None	None
Carbon Dioxide	5,000ppm	30,000ppm	None
Carbon Monoxide	35ppm	None	200ppm
Helium	None	None	None
Hydrogen Fluoride	3ppm	None	6ppm
Nitric Oxide	25ppm	None	None
Nitrogen	None	None	None
Nitrogen Dioxide	None	1ppm	None
Ozone	None	None	0.1ppm
Phosgene	0.1ppm	None	0.2ppm

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.

• Aluminum
• Antimony
• Arsenic
• Beryllium
• Cadmium
• Chromium
• Cobalt
• Copper
• Iron Oxide
• Lead
• Manganese
• Molybdenum
• Nickel
• Silver
• Tin, organic
• Tin oxide & inorganic
• Titanium
• Vanadium
• Zinc Oxide
• Argon*
• Carbon Dioxide
• Carbon Monoxide
• Helium*
• Hydrogen Fluoride
• Nitric Oxide
• Nitrogen*
• Nitrogen Dioxide
• Ozone
• Phosgene

* 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.