Welding, Manganese Fumes, and Related Negative Health Effects

Manganese: Both Healthy & Toxic

Manganese, a naturally-occurring element, is a very important component for a variety of manufacturing and industrial operations, especially iron and steel production. It is also considered to be an essential nutrient for humans. It assists in a variety of bodily processes, including antioxidant function, metabolism, bone development, and wound healing [3]. It can be found in “pecans, peanuts, pineapple fruit and juice, oatmeal, shredded wheat, and raisin bran cereal. Good sources are beans (pinto, lima, navy), rice, spinach, sweet potato, and whole wheat bread” according to www.nutrimirror.com.

In a healthy individual with proper immune and organ function, normal amounts of ingested Manganese can be digested and disposed of with ease. [Visit the Food and Nutrition Board (FNB) of the Institute of Medicine website to search for Adequate Intake Amounts of Manganese].

Although Manganese is an essential nutrient for humans, it can become toxic at certain exposure levels; especially when Manganese fumes are inhaled. Instead of going through the body’s normal defense mechanisms, the fumes bypass them, accumulate, and subsequently damage vital organs like the lungs, liver, kidney and central nervous system according to the National Institute for Occupational Safety and Health (NIOSH). [1]

Short-term exposure may lead to metal fume fever, which symptoms include fever, chills, nausea, fatigue, muscle ache, joint pain, and thirst, among others. These symptoms usually resolve themselves within 24-48; however, long-term and chronic exposure to manganese fumes can lead to a disease called Manganism which has symptoms similar to those related to Parkinsons.


Manganism (manganese poisoning) can develop from chronic exposure to manganese-containing fumes. Symptoms may include:
    • Tremors
    • Slowed Movement
    • Walking Problems
    • Shakes
    • Loss of Balance
    • Impotency
    • Slurred Speech
    • Extreme Drowsiness
    • Muscle Rigidity [1] [2]
Occupational Risk
Typical occupations that run the risk of overexposure to manganese fumes include workers in the following fields according to NIOSH:
    • Mining
    • Ore-Crushing
    • Metallurgical Operations for iron, steel, ferrous and nonferrous alloys
    • Manufacturing of:
      • Dry-cell batteries
      • Anti-knock gasoline additives
      • Pesticides
      • Pigments
      • Dyes
      • Inks
    • Welding Operations [1]
    • Other occupations that involve the release of manganese-containing fumes
Welding & Manganese
Workers can be exposed to Manganese fumes during a variety of welding operations; it is difficult to be specific because of differences in and multiple combinations of welding wire, fluxes, and base metals.

NIOSH explains that welders who work with lead, iron and manganese may be at increased risk for neurological health effects. [They also note that “heat and stress can also contribute to neurological impairments in welders.”] A recent study showed poorer performance on brain function and motor skill tests from welders who were exposed to low levels of Manganese (3). Health effects also included “changes in mood and short-term memory, altered reaction time, and reduced hand-eye coordination. It is not known if these findings have clinical significance.” [1]

The chart below shows Occupational Exposure Limits for Manganese from NIOSH, OSHA, and ACGIH:

Occupational Exposure Limits for Manganese

Agency Occupational Exposure Limit
NIOSH REL 1 mg/m3 (TWA) and 3 mg/m3 (STEL)
NIOSH IDLH 500 mg/m3
OSHA PEL 5 mg/m3 (ceiling)
ACGIH TLV 0.2 mg/m3(TWA)
IDLH: immediately dangerous to life and health concentration
PEL: permissible exposure limit
REL: recommended exposure limit
STEL: short-term exposure limit
TLV: threshold limit value
TWA: time-weighted average
Engineering Controls

Respirators and local exhaust ventilation, also known as fume extractors, (example shown below) are typically the recommended engineering controls for welding fume control; however, a Certified Industrial Hygienist should be consulted in order to determine the best safety approach based on the amount of fumes produced, materials involved, and environmental considerations. [See “Exposure Sources and Control Methods” on OSHA’s webpage dedicated to Occupational Safety and Health Guideline for Welding Fumes for further information].

Local Exhaust Ventilation: Model 400 Welding Fume Extractor
Local Exhaust Ventilation: Model 400 Welding Fume Extractor
Ductless Fume Hoods are another local exhaust option for applications that release manganese fumes and are performed on a small scale or limited space environment

For additional information on Local Exhaust Ventilation for Welding Fume Control, give Sentry Air a call at 1.800.799.4609, email us at sales@sentryair.com, or fill out this form to receive more information.


[1] “Welding and Manganese: Potential Neurologic Effects.” NIOSH. <http://www.cdc.gov/niosh/topics/welding/>
[2] “Welding and Manganese Poisoning”. International Brotherhood of Electrical Workers. <http://www.ibew.org/articles/03journal/030708/p8.htm>

[3] “Manganese”. Linus Pauling Institute,Oregon State University <http://lpi.oregonstate.edu/infocenter/minerals/manganese/>

Other Helpful Information:

NIOSH Pocket Guide to Chemical Hazards: Manganese compounds and fume (as Mn)>

“ToxFAQ’s for Manganese”. Agency for Toxic Substances & Disease Registry. <

*** This blog entry was written as a customer service and no representation is made as to the completeness or accuracy of the information it contains. Persons that believe they have been overexposed to manganese fumes should consult a healthcare physician or seek medical assistance. If you believe you are being exposed to these fumes in your workplace, consult a industrial safety officer or management team regarding this issue.