Metal Fume Fever: Causes and Prevention

Welder’s flu. Zinc shakes. Galvie flu. The brass shakes. Monday morning fever. Welders and metalworkers have a lot of different names for a common problem in the industry: metal fume fever. What is metal fume fever, who is at risk, and what can be done to prevent it? While this occupational illness can be serious if left untreated, it is entirely preventable with the right engineering controls. 

What Is Metal Fume Fever?

Metal fume fever, often known as “welder’s flu” or “welding fume fever,” is an occupational health hazard typically faced by people who work with metals, particularly in welding or hot metal processing. This condition is caused by the inhalation of metal oxide fumes, which can happen if a person is exposed to certain types of metals at high temperatures.

When metals such as zinc, copper, aluminum, cadmium, or iron are heated, they can give off fumes that, when inhaled, can cause a range of symptoms similar to those of influenza or the flu. Symptoms usually manifest a few hours after exposure and will typically resolve on their own 24-48 hours after exposure ceases. However, repeated long-term exposure can lead to more serious health impacts. 

Who Is at Risk for Metal Fume Fever?

Metal fume fever is primarily an occupational illness, meaning that those at risk are typically individuals working in industries or environments where exposure to metal fumes is possible. It is most commonly associated with welding, but other thermal processes—including plasma or laser cutting, brazing and soldering, smelting, foundry work, surface preparation and heat treating—can also create fumed metal oxides that put workers at risk. Some forms of grinding may also create enough fine particulate to cause symptoms of metal flu. Galvanizing, which creates fumed zinc oxide, and working with galvanized steel create a high risk of metal fume fever. 

Metals most commonly associated with metal fume fever include zinc (used for galvanized metals), copper, magnesium, aluminum and iron. While less common, silver, beryllium and lead are also known to cause welder’s flu. Workers exposed to these metals in fumed, inhalable form are at risk. 

In addition to welders and metalworkers, occupations with a high risk of metal fume fever include: 

• Blacksmiths
• Smelters
• Jewelry makers
• Construction workers
• Battery manufacturers
• Firefighters

Symptoms of Metal Fume Fever

Symptoms of metal fume fever are similar to those of infectious influenza and can include fever, chills, nausea, fatigue, muscle ache, joint pain, lack of appetite, shortness of breath and a metallic taste in the mouth. They usually appear within 3-10 hours of exposure to fumed metal oxides. 

• Fever and Chills: One of the primary symptoms of metal fume fever is a high temperature, often accompanied by chills. (This is why the illness is often called the “welding shivers.”) 
• Muscle and Joint Pain: Aching muscles and joint pain are common and can sometimes be severe.
• Nausea and Vomiting: The metallic fumes inhaled can cause an upset stomach, resulting in feelings of nausea and, occasionally, vomiting.
• Fatigue: A general feeling of tiredness or weakness is common in individuals with metal fume fever.
• Shortness of Breath: In some cases, individuals may experience breathing difficulties.
• Lack of Appetite: Loss of appetite is a common symptom of many illnesses, including metal fume fever.
• Metallic Taste in the Mouth: This is a characteristic symptom of metal fume fever, likely due to the inhalation of metallic fumes.

Symptoms usually peak within the first 24 hours and, provided further exposure is avoided, generally resolve within 24 to 48 hours. It’s important for anyone who suspects they may have metal fume fever to seek immediate medical attention and provide their healthcare provider with as much information as possible about their symptoms and potential exposure to metal fumes.

Diagnosis of Metal Fume Fever

Diagnosing metal fume fever can be a bit of a challenge due to its symptoms mimicking those of common viral illnesses. The diagnosis of metal fume fever often ends up being a diagnosis of exclusion, meaning that other causes for the symptoms (such as exposure to infectious disease) are ruled out. One key aspect that often supports the diagnosis is the pattern of the symptoms—if they tend to occur after exposure to metal fumes and resolve when exposure is avoided, it’s more likely to be metal fume fever.

A suspected diagnosis of metal fume fever can be confirmed (and other conditions ruled out) by a medical examination, imaging and laboratory testing. 

1. Medical History: An important step in diagnosing metal fume fever is understanding the patient’s medical and occupational history. The doctor will ask about the patient’s symptoms, how long they’ve been experiencing them, and if they’ve been exposed to metal fumes at work or elsewhere. The timing of symptom onset in relation to work exposure can be a significant clue.
2. Physical Examination: A physical examination can be conducted to assess the patient’s overall health and identify any signs of illness. The doctor might listen to the patient’s lungs, check their temperature, and look for other signs of infection or inflammation.
3. Laboratory Tests: Blood tests may be done to detect inflammation or other abnormalities. While there’s no specific blood test to diagnose metal fume fever, certain changes like an elevated white blood cell count might suggest an inflammatory response. Urine tests might also be used to measure levels of certain metals (such as zinc), though these are not always elevated in metal fume fever.
4. Imaging Tests: Chest X-rays or other imaging tests might be used to check for any lung damage or abnormalities. However, in most cases of metal fume fever, these tests come back normal.

Metal Fume Fever vs. “The Flu”

Metal fume fever and the flu (influenza) have overlapping symptoms, which can make differentiation difficult. Both can present with fever, chills, muscle aches and fatigue. However, there are a few key differences.

• Cause: The most significant difference is the cause. The flu is a contagious respiratory illness caused by influenza viruses, whereas metal fume fever is an industrial illness caused by the inhalation of certain metal fumes.
• Exposure: Metal fume fever is strongly linked to occupational exposure. Symptoms typically arise several hours after a person has been exposed to metal fumes, often in a workplace setting like welding or metallurgy. Flu, on the other hand, is contracted through contact with an infected person or by touching surfaces contaminated by the flu virus.
• Metallic Taste: A distinctive metallic taste in the mouth is a common symptom of metal fume fever, but not a symptom typically associated with influenza.
• Symptom Duration: Symptoms of the flu usually last longer, often for a week or more, while symptoms of metal fume fever usually resolve within 24-48 hours after the cessation of exposure to metal fumes.
• Prevention: Flu can be prevented through vaccination and good hygiene practices. In contrast, metal fume fever is prevented through occupational safety measures like adequate ventilation, the use of respiratory protective equipment, and proper handling and processing of metals.
• Pattern of Symptoms: In cases of metal fume fever, symptoms often improve or completely resolve when the person is away from the workplace or exposure source, such as over the weekend, and return once they’re back at work. This pattern is not seen with the flu.

How Serious Is Metal Fume Fever?

Metal fume fever, in most cases, is a self-limiting illness that typically resolves within 24-48 hours after the cessation of exposure to the offending metal fumes. However, the severity and potential long-term effects can vary based on factors like the type of metal involved, the concentration and duration of exposure, and the individual’s overall health.

While the symptoms can be quite unpleasant, similar to a severe flu, they usually do not cause long-term harm if exposure is promptly identified and mitigated. Symptoms such as fever, chills, muscle aches, cough, shortness of breath, and fatigue can disrupt daily activities and lead to a temporary decrease in work performance and quality of life. However, repeated, long-term exposure to certain metal fumes, especially in the absence of proper safety measures, can potentially lead to more serious health conditions such as the following.

• Chronic Respiratory Conditions: Frequent and sustained exposure can lead to chronic bronchitis, industrial or occupational asthma, or other persistent respiratory conditions.
• Lung Damage: Certain metals, such as cadmium, can cause severe lung damage when their fumes are inhaled over a prolonged period, potentially leading to life-threatening conditions like pulmonary edema.
• Neurological Effects: Overexposure to manganese fumes, for instance, can lead to manganism, a Parkinson’s disease-like syndrome.
• Cancer Risk: Long-term exposure to certain metal fumes, such as those from hexavalent chromium and nickel, is associated with an increased risk of lung cancer.

Due to these potential risks, it’s important for workplaces where metal fumes are present to enforce strict safety protocols, including proper ventilation, use of personal protective equipment, regular monitoring of air quality, and health surveillance of workers. Any symptoms of metal fume fever should be taken seriously, and affected individuals should seek immediate medical attention.

What To Do If You Suspect Metal Fume Fever

If you or someone you know is exhibiting signs of metal fume fever, the most important thing to do is remove the exposure as soon as possible. Get away from fume-producing processes and into fresh air. The sooner you can eliminate exposure to harmful welding and metalworking fumes, the sooner recovery can start. If metal fume fever is suspected, it is also important to seek medical attention. Metal fume fever can be serious; seek help from your primary care physician or an urgent care center right away. If you are having difficulty breathing, call an ambulance or go to the nearest emergency room immediately.  

Other steps you can take to alleviate the symptoms of metal fume fever include: 

• Drink lots of fluids to flush toxins out of the body and speed recovery. 
• Rest until symptoms subside. 
• Follow up with your health care provider if symptoms do not subside on their own within 48 hours. 

If the incident occurred in a workplace setting, it should be reported to health and safety officers. The Occupational Safety and Health Administration (OSHA) may require some employers to document and report cases of metal fume fever. Be sure to follow all reporting requirements for your jurisdiction. It is also critical to take steps to identify the source of exposure and prevent future cases of metal fume fever. 

Preventing Metal Fume Fever

Metal fume fever is entirely preventable by eliminating exposure to fumed, inhalable metals and metal oxides. Employers have a duty to provide a safe and healthy workplace, which includes ensuring that workers are not exposed to hazardous emissions at levels above the OSHA Permissible Exposure Limit (PEL). This can be done through a combination of engineering controls (e.g., air filtration and ventilation) and personal protective equipment (PPE). Note that the “Hierarchy of Controls” mandates that employers must attempt engineering controls before relying on PPE; PPE should only be used as a last resort in environments where it is not technically feasible to meet the standard through engineering controls alone. 

Source Capture of Fumes

Source capture is the gold standard for weld fume extraction and control of dust and fumes from other industrial processes. With a source capture system, fumes and particulate are collected as close to the generation source as possible. This keeps them out of the worker’s breathing zone and prevents fumes from propagating through the facility. 

• Robotic processes can be kept under a source capture hood or enclosure. No workers should be inside the hood during production processes. 
• Manual welding fumes can be collected using a fume gun (for MIG welding only) or via a backdraft plenum or fume arm. A downdraft table may be suitable for other processes (such as manual cutting or grinding). 
• The hood should be ducted to an industrial dust collector to capture fumes and filter the air.   

Ambient Air Filtration and Ventilation

If source capture is not possible or practical, or is not sufficient to meet the OSHA PEL, an ambient air filtration system may be used. These systems clean the air for the entire facility. The system should be designed to pull dirty air away from the breathing zone for workers and return clean, filtered air to the facility. In light-production environments, it may be possible to use simple exhaust ventilation to remove fumes from the facility. Make sure there is plenty of fresh make-up air coming into the room to keep fume concentrations under the OSHA PEL. (Learn more about Industrial Air Filtration and Ventilation.) 

Personal Protective Equipment (PPE)

Personal protective equipment (PPE), including respirators, can help protect workers from inhaling metal fumes. The type of respirator needed can depend on factors like the type of metal, the process, and the concentration of fumes. PPE should be used in environments where engineering controls are not technically feasible or are not sufficient to meet the PEL. Workers should be fit-tested for respirators and trained in their use and maintenance.

Other Protective Measures

Minimizing exposure to dangerous metal fumes will prevent most cases of metal fume fever. In addition to fume control and PPE, employers can take other steps to protect workers from metal dust and fumes. 

• Implement safe work practices: Training workers in safe work practices can reduce exposure to metal fumes. This could include techniques for reducing fume production, such as using a lower voltage for welding operations.
• Monitor air quality: Regularly measuring the concentration of metal fumes in the air can help ensure that ventilation and protective measures are adequate.
• Substitute hazardous materials: If possible, use materials or processes that generate fewer or less toxic fumes. For instance, cold cutting methods might be used instead of thermal cutting where appropriate.
• Health surveillance: Regular health check-ups can help to detect signs of health issues related to metal fume exposure early.
• Good personal hygiene: Workers should wash their hands and face before eating, drinking, or smoking, and shower before leaving the worksite to prevent ingestion of metal particles.
• Training: Workers should be trained about the hazards associated with their work, the symptoms of metal fume fever, and the importance of reporting any symptoms immediately.

Keep Workers Safe from Metal Fume Fever

If workers in your facility have experienced metal fume fever, it is important to take immediate steps to reduce fume exposure and bring the facility into compliance with OSHA regulations for indoor air quality. Reducing occupational exposures to weld fumes and other sources of fumed metals and metal oxides will minimize the risk of acute occupational illness such as metal fume fever or long-term health impacts. 

RoboVent can conduct facility testing to identify sources of metal fume exposure and recommend engineering controls to mitigate the risks. Effective air filtration and ventilation will protect workers and create a safe, comfortable and healthy workplace. 

Contact an air quality expert.