Why do welders wear masks?
Welders understand that the fumes and gases produced from their work can lead to serious illness. The danger and amount of exposure to the welders depend on the type of work being done, the rod, filler metals, base metals, coatings, contaminants, as well as the amount of ventilation and respiration protection.
We simply don't know everything there is to know about protecting workers from welding fumes. However, there are some common precautions that can be taken to protect workers from injury and illness.
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Welding fumes are a mixture of metallic oxides, fluorides, and silicates. Not so wonderful to be breathing into your lungs by themselves, but since we have to live and work in the real world, there are other considerations such as the paint, rust inhibitors, solvents, and other coatings on the welded metal which can create additional dangers.
Why do welders drink milk?
If you are looking for some entertainment one day, sit down with a group of seasoned and rookie welders and ask them the question, "Why Do Welders Drink Milk", and you will more than likely encounter some very heated discussions on the topic…no pun intended.
I have heard stories of welders loading up on milk like marathoners loading up on carbs. Some swear by the advice, stating that they never leave home without it. Others say it is nothing more than an old wives' tale and shouldn't be relied upon.
So why do welders drink milk? The fumes released when welding, cutting or brazing galvanized steel can cause a condition known as Metal Fume Fever. The thought is that milk helps the body rid of toxins encountered when welding galvanized steel and thus prevents them from getting sick.
The Galvanized Steel is iron coated with zinc. The iron is put into a zinc coating where the zinc has a chemical reaction with the metal base. The outer layer contains pure zinc alloy. The inner layer, on the other hand, relies on pure iron.
The layers in between comprise part of zinc and iron base metal. The zinc oxide can be found in Galvanized Steel. It can be seen in the various percentages of iron and zinc. The white powder used by lifeguards to avoid sunburn contains zinc oxide.
It does not matter if you are new to Galvanized Steel welding or old, proper precautions must be taken. Taking necessary safety measures can reduce exposure to zinc oxide fumes by a high margin.
At the time of preparing the base metal, try to remove as much zinc from the metal surface as you can. Galvanizing often displays a yellow-green smoke, white residue on the weld and white powdery particles in the air.
What are the symptoms of galvanized poisoning?
If you ever find yourself in the middle of a giant yellowish-green fumes, you might be a victim of Galvanize poisoning. Too much exposure to zinc oxide in the fumes may cause poisoning. The more you are exposed to these fumes, the more severe the galvanize poisoning will become. You should take necessary precautions before exposing to zinc oxide mixed fumes.
Symptoms of flu are similar to the symptoms of galvanizing poisoning. Soon after being overly exposed to zinc oxide, the patient's body starts to show the signs. It begins with a mild headache and nausea. In severe cases where people get too exposed to zinc oxide may result in all kinds of symptoms, similar to the flu. Moderate exposure will cause shaking, chills, cold sweats, fever, and vomiting.
As a welder, if you experience any of these symptoms, you need to give it a break and get some fresh air right then. If the exposure crosses the limit, it may cause death. If you experience symptoms worse than the ones mentioned above, you should immediately seek medical attention.
Galvanize poisoning is something that lasts for a short period. The early symptoms start showing by hours of being exposed. These symptoms should disappear within 24 hours. If you have been exposed for a longer period of time, it may take 48 hours. Drinking milk is advised to hasten the healing process. The calcium in the milk helps to remove the zinc from your body.
What is metal fume fever, and what causes it?
In order to protect steel, it is sometimes put through a galvanization process. By galvanizing steel, you are essentially coating it with zinc which acts as a barrier to the base metal (e.g. steel) and prevents it from corrosion or rusting.
The problem is, however, when you are welding or heating galvanized steel, the fumes are vaporized as the zinc coating melts at a much lower temperature than steel. Metal fume fever is a condition that produces flu-like symptoms when someone inhales the fumes from welding, brazing or cutting galvanized steel. It is also called brass shakes, zinc shakes, galvie flu, metal dust fever, Monday morning fever, spelter shakes or welding shivers.
The dust or fumes released contain oxides (mostly zinc oxide) which can cause headaches, fever, chills, muscle aches, nausea, fatigue, joint pain, changes in blood pressure, chest pains, shortness of breath and pneumonia. The symptoms will usually show up within a few hours of the initial exposure and last anywhere from 24-48 hours in total. However, repeated exposure to welders' fume fever seems to form a tolerance to the fumes themselves.
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The tolerance, however, only lasts when there is a level of continuous exposure. So if you are around the fumes for the duration of the workweek, once you take a break from exposure (ex. the weekend), the symptoms will then appear as the tolerance has disappeared. This is where the name Monday morning fever came from. There is no documentation as to what prolonged, repeated exposure will cause. OSHA has a permissible exposure limit of 5 milligrams of zinc oxide fume per cubic meter of air (mg/m3) average in an 8-hour work shift.
If you have any of the symptoms above, contact a medical professional and be sure to disclose the exposure.
Metal Fume Fever ( MFF) is an acute, fever-based illness caused when welders inhale microscopic zinc oxide particles. These particles are found in the welding smoke (fume) created on the job. Essentially, MFF causes flu-like symptoms in welders breathing in too many particles at one time. Luckily, in most cases, symptoms normally go away after just a day or so, even without medical treatment. MFF has been reported to be caused by inhaled exposure to other metal oxides on the job site as well (namely copper, iron, and magnesium). However, it remains to be most frequently caused by zinc oxide.
Estimates by the NCBI (National Center for Biotechnology Information) show that between 1,500 to 2,500 welders will develop MFF annually. This makes it a fairly common affliction in many, and especially long term, welding employees.
While Metal Fume Fever is the common name for this occupational hazard, people may also know it by other "nicknames." Some of them are brass founders ague (another word for a fever based illness), the metal shakes, spelter's shakes, the zinc chills, and the zinc fever. The first documentation of MFF was in the mid-1800s. It remains a common diagnosis for welders.
What are the signs and symptoms of metal fume fever?
Most welders who come down with Metal Fume Fever say that they first noticed the signs and symptoms 3 to 10 hours after exposure. They describe them similarly to how people describe the common cold. This includes any combination of the following (however, there must be a fever for an official MFF diagnosis) :
- Fever (of no higher than 102 degrees Fahrenheit)
- Chills (where the name "the zinc chills" comes from)
- Excessive Sweating
- Muscle and/or joint pain
- Extreme fatigue
- Shortness of breath
More commonly, welders with MFF will complain of a low fever, feeling more worn down than usual, sore muscles, and headache. The doctor will start with blood work. In most cases, the white blood cell count (WBCs) will be higher than they should be (usually around 12,000 to 16,000 mm³). Normal is anywhere from 4,000 to 11,000 mm³ in a healthy welder.
There are also a few, less common but still trademark signs and symptoms to take into account as well :
- A sweet, metallic taste in the mouth
- Throat pain
- Increased thirst
- Trouble breathing, possibly painful
- Chest pain
Many doctors will also perform a chest x-ray to rule out other issues that may be causing the same symptoms. In the majority of healthy welders, the chest x-ray won't show any significant issues. However, welders that have repeated exposure over their career or have had MFF multiple times are at higher risk. They may show signs of occupational asthma or the worsening of any pre-existing heart and lung conditions. However, keep in mind that this hasn't been conclusively proven! While MFF does not normally need to be specifically treated, an abnormal chest x-ray may prompt additional testing and care.
When does MFF become a bigger issue?
Symptoms of a larger, non-MFF issue include pulmonary infiltrates on the chest x-ray and a low blood oxygen level (hypoxemia). These are also common with toxicity from more dangerous metals (cadmium or nitrogen oxide) and require significantly more medical care.
Ultimately, a final diagnosis of MFF is based on your symptoms and your job description alone. There is no actual test, and it may be missed if you don't let your doctor know what you do for a living.
What are the causes of metal fume fever?
MFF can only be caused by inhaled exposure of zinc oxide. It can not happen as a result of the skin or oral exposure. Zinc oxide particles are most prevalent on job sites where there is no appropriate ventilation system in place.
While there haven't been too many studies on the mechanism of toxicity (how/why zinc oxide causes the body to react to it as a poison), the most popular current scientific theory is that it affects the cytokine in the body and specifically in the lungs.
Cytokine cells are the molecules in our bodies that talk to each other, and other cells. They then direct them to the areas that need an immune response. This means the cytokine tells the body to attack zinc in the same way it would attack a virus (like a cold), which is why MFF has similar symptoms. Inhaling zinc oxide causes the body's immune system to turn on, switch into high gear, and take out the bad guys. This factor makes MFF different from an allergy and allows for it to be a health issue for welders as early as the first time you are exposed.
The category of welding process (fusion or pressure welding, as well as the specific type). The safest arc welding type currently available is the Tungsten Inert Gas (TIG or GTAW) style. The least safe is the Flux Core Arc Welding (FCAW) style.
The base metal, filler metals and the composition of the welding rod
Where the welding is happening (outside/inside, enclosed spaces)
Appropriate ventilation controls and air movement
What Factors Affect Metal Fume Fever?
The worker in overalls and a respirator. Protective attire of technical workers.
There are a variety of factors that can affect the amount of exposure that welders have to fumes. Knowing them can reduce the likelihood of developing MFF.
In addition, MFF is most likely to occur at the beginning of the workweek. This has led to some people humorously nicknaming it the Monday Morning Fever! It affects far more men than women as well. However, this is likely because there are more men than women employed in welding at this time.
How Can MFF Be Dangerous?
While MFF isn't dangerous, longterm exposure to large amounts of zinc oxide during a career may contribute to occupational asthma. Again, as stated above, this link has not yet been proven. There was also a study in England where a tradesman diagnosed with MFF ended up with more significant health problems. These issues – aseptic meningitis (inflammation of the brain and spinal cord) and pericarditis (inflammation around the heart) were directly associated to their exposure. However, these cases are very few and far between and haven't been officially correlated with MFF in any medical studies.
There are other studies showing that longterm exposure to fumes created during welding can also lead to other health issues. This includes pneumonia (which can be severe and even fatal in those with lowered immune systems) and even cancer. These are not related to MFF.
Is There a Toxic Zinc Dose?
Resistance to zinc oxide poisoning can develop as quickly as exposure multiple days in a row (called "tachyphylaxis"). However, the ACGIH (American Conference of Governmental Industrial Hygienists) identifies a toxic dose that counts as an actual emergency situation. The IDLH ("immediately dangerous to life or health") level is any zinc oxide amount over 500 mg/m³, which can be fatal.
It is also important to note that some welders may develop an allergic or asthmatic response to the zinc oxide fumes (in some cases, an anaphylactic reaction). This is separate from MFF as well.
How Can I Prevent Metal Fume Fever?
It is preventing excessive zinc exposure while welding starts with having a supportive workplace that follows all applicable OSHA regulations. Part of that is the measurement (every 8 hours) of the ambient zinc concentrations in different areas. The PEL (permissible exposure limit) is any zinc oxide measurement below 5 mg/m³ over an eight-hour workday. Anything above that must be addressed and mediated by the business ASAP. This is a legal OSHA guideline.
In addition, all welding business owners must provide information and training to all of their employees. This must include posted guidelines, annual training, and testing to verify that every employee understands what MFF is and how to prevent it. OSHA will require proof as well.
Business owners should also consider upgrading equipment, especially any that have to do with safety engineering controls. This includes welding fume extractors (local exhaust ventilation and source-capture), which increases the safety of their employees.
TREATMENT OF METAL FUME FEVER
Traditional treatment of metal fume fever is similar to the treatment of any other type of flu symptoms. Getting plenty of rest and staying hydrated is the key. Symptoms such as headache, body aches, and joint pain, aspirin or ibuprofen are sufficient. It has been said that drinking milk prior to or immediately after welding on galvanized steel aids in the ridding of toxins that are inhaled from the fumes.
Some believe it needs to be in your system for a period of time before starting. Others have said they will fill their mouths full of milk and spit it out repeatedly over time, indicating that the milk has now turned to a greenish colour. There is no conclusive evidence that drinking milk helps prevent metal fume fever.
PREVENTION OF METAL FUME FEVER
Whether or not you think that drinking milk is a myth, there are several other things that you can do to ensure that you are limiting or preventing yourself from exposure in the first place. The first step is to keep your head out of the fumes and use local exhaust and/or general ventilation to reduce your exposure to the fumes.
If you are not sure that the ventilation or exhaust is sufficient, check your exposure to the Threshold Limit Values (TLV) or the MSDS (Material Safety Data Sheets). You can have a qualified individual monitor and measure the exposure. You should also wear an approved respirator if you know you will be working with galvanized steel, especially if ventilation or proper exhaust is not known.
Your respirator should be approved by the Mine Safety and Health Administration (MSHA) or by the National Institute for Occupational Safety and Health (NIOSH). Some respirators work to take the toxic particles out of the air while others work to provide clean air from some other source. Make sure you know how to use the respirator. Putting one on without knowing how it should be used is pointless. Training is generally required if you are required to use a respirator. The training should at a minimum include information on how to use the respirator, capabilities, limitations, maintenance, and storage.
The last option would be to remove the zinc by using a grinding process. This will ultimately leave the metal unprotected, but depending on the amount being used, you could always apply a protective coating after it has been welded. Grinding will just take more time in the process.
There will be two types of welders reading this article. The first will think this is a joke that no one could seriously believe that milk would be a suitable shield against a now known carcinogen. The other has heard from their peers that drinking milk does protect them from welding fume and wants to know whether there is any truth to this tale. Below, we take a look at the facts and give you the answers once and for all.
Drinking milk to protect you from welding fume
The first concept is that after drinking milk, the body will absorb the calcium from the milk, and this will "fill up" the spaces that other heavy metals like zinc and cadmium would otherwise fill. By filling these gaps, the welder lowers the potential intake of these heavy metals.
While the body will absorb calcium, this process relies on the digestion system pathway, NOT the respiratory system. Therefore, the heavy metals that make their way into the respiratory pathway by breathing in welding fume are in no way affected by the intake of milk through the digestion system. Furthermore, a healthy diet means there should be no calcium deficiency, so the extra calcium in the milk will not be absorbed (or very little).
Holding milk in the mouth while welding acts as a filter
The other theory is that welders would hold the milk in their mouth while welding. After welding, they would spit the now dirty milk out! Trying to use it as a scrubber solution.
The whole notion is wrong. Holding the milk in your mouth forces the welder to breathe through their nose. Again, this process relies on the respiratory system with the welding fume being transported to the welder's lungs. A respirator worn and used correctly will be more effective at preventing the welding fumes from getting into the welders' airways to start with, rather than attempting to do something after the fumes have already entered the body.
When working with galvanized steel, it is important that you understand your environment and the equipment you are working with. You should take the time to understand the ventilation and exhaust situation in which you are working.
If they are not adequate, you must wear an approved respirator. Another option is to grind the zinc off before welding is performed. It seems as though drinking milk to prevent Metal Fume Fever is an old wives' tale. There is no solid scientific evidence to suggest that it helps rid the toxins from your system. However, unless you are lactose intolerant, there is nothing that states that it causes any harm.