Metal fume fever
|Metal fume fever|
|Classification and external resources|
Metal fume fever, also known as brass founders' ague, brass shakes, zinc shakes, galvie flu, metal dust fever, or Monday morning fever, is an illness caused primarily by exposure to certain fumes. Workers breathe in fumes from chemicals such as zinc oxide (ZnO) or magnesium oxide (MgO), which are themselves created by heating or welding certain metals, particularly galvanized steel. Other common sources are fuming silver, gold, or platinum metals. Chromium is also a hazard, from stainless steel. Cadmium, present in some older silver solder alloys can, in extreme cases, cause loss of consciousness within a matter of minutes.
Signs and symptoms
The signs and symptoms are nonspecific but are generally flu-like including fever, chills, nausea, headache, fatigue, muscle aches, joint pains, lack of appetite, shortness of breath, pneumonia, chest pain, blood pressure change, and cough. A sweet or metallic taste in the mouth may also be reported along with a dry or irritated throat which may lead to hoarseness. Symptoms of a more severe metal toxicity may also include a burning sensation in the body, shock, no urine output, collapse, convulsions, shortness of breath, yellow eyes or yellow skin, rash, vomiting, watery or bloody diarrhea or low or high blood pressure, which require prompt medical attention. Flu-like symptoms will normally disappear within 24 to 48 hours. It often takes one to three weeks to fully recover.
Metal fume fever is due to the inhalation of certain metals, either as fine dust or most commonly as fumes. Simple compounds of the metals, such as their oxides, are equally capable of causing it. The effects of particularly toxic compounds, such as nickel carbonyl, are not considered as a mere metal fume fever.
Exposure usually arises through hot metalworking processes, such as smelting and casting of zinc alloys, or welding of galvanized metals. If the metal concerned is particularly high-risk, then cold sanding processes may also cause it, even though the dose is lower. This may also occur with electroplated surfaces or metal-rich anti-corrosion paint, such as cadmium passivated steel or zinc chromate primer on aluminium aircraft parts. Exposure has also been reported in use of lead free ammunition, by the harder steel core stripping excess metal from the jacket of the bullet and barrel of the rifle.
The most plausible mechanism accounting for the symptoms involves a dose-dependent release of certain cytokines, an event which occurs by inhaled metal oxide fumes which injure the lung cells. This is not an allergic reaction, though allergic reactions to metal fumes can occur.
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There will be people who don’t get ill but some welders do get ill from breathing welding fume. Some may be ill for only a short time, others may get permanent illnesses like asthma. There is no easy way to know if it will be you. A few welders get so ill they have to stop welding and find a new career.
So what can happen to you if you regularly breathe in welding fume? Pneumonia Welders are particularly prone to a lung infection that can lead to severe and sometimes fatal pneumonia.
Modern antibiotics usually stop the infection however in severe cases you could end up in hospital. HSE estimate that breathing metal fume at work leads to 40-50 welders each year being hospitalised. Pneumonia kills about 2 welders* each year. It can affect young welders as well as older people.
Exposure to welding fume in the past does not increase the chances of you getting pneumonia now.
- Palmer et al. (2009). Mortality from infectious pneumonia in metal workers: a comparison with deaths from asthma in occupations exposed to respiratory sensitizers. THORAX Online first, published on August 23, 2009 as 10.1136/thx2009.114280
Occupational asthma In a recent review PDF HSE found that the scientific evidence relating to welding fume and asthma was not strong enough for HSE to list welding fume as a confirmed cause of asthma. However, we know that about 9 welders, each year, get asthma so badly that they are able to claim benefits (Industrial Injuries and Disablement Benefit). HSE advises welders to protect themselves and follow the safe way of working that their employer should provide for them. Stainless steel fume has chromium oxide (CrO3) and Nickel Oxide in it. Both these chemicals can cause asthma. For this reason, stainless steel welding fume is considered more harmful than mild steel fume.
Phil Hydes video interview Cancer Welding fume is internationally classified as possibly carcinogenic to humans (IARC classification group 2B). Although primarily associated with stainless steel welding, this classification is not limited to stainless steel fume. It covers all welding fume. The UK system of classifying substances (Chemicals (Hazard Information and Packaging for Supply) Regulations 2009 link to external website) does not consider by-products of a process. This means that welding fume is not currently assigned a hazard classification.
Further information A scientific review paper PDF HSE presented to the Working Group on Action to Control Chemicals (WATCH) committee in 2010 International Agency for Research on Cancer, Monographs on the evaluation of carcinogenic risk to humans Vol 49 link to external website, chromium, nickel and welding. Metal fume fever Many welders report flu like symptoms after welding. The effects are often worse at the start of the working week. Metal fume fever is usually linked to welding or hot work on galvanised metals. High exposures to mild steel weld fume can also cause this illness. Metal fume fever does not usually have any lasting ill effects. Don’t believe the stories about drinking milk before welding. It does not prevent you getting metal fume fever.
Irritation of throat and lungs Gases and fine particles in welding fume can cause dryness of the throat, tickling, coughing or a tight chest. The effects tend to be short lived. Ozone is a particular cause of this when TIG welding stainless steels and aluminium. High exposures to nitrous oxides (generated during most arc welding operations) can also cause this health effect. Extreme exposure to ozone can cause pulmonary oedema (fluid on the lungs)
Temporary reduced lung function Overall lung capacity and the ease at which you can breathe out (peak flow) are affected by prolonged exposure to welding fume. The effects tend to get worse through the working week but gradually improve when not exposed (e.g. over the weekend).
Diagnosis primarily depends upon a good occupational history. Diagnosis of metal fume fever can be easily missed, as the complaints are non-specific, resemble a number of other common illnesses, and presentation occurs typically 1–4 days after the exposure. When respiratory symptoms are prominent, metal fume fever may be confused with acute bronchitis or pneumonia. The diagnosis is based primarily upon a history of exposure to metal oxide fumes. Cain and Fletcher (2010) report a case of metal fume fever that was diagnosed only by taking a full occupational history and by close collaboration between primary and secondary health care personnel.
Physical examination findings vary among persons exposed, depending largely upon the stage in the course of the syndrome during which examination occurs. Patients may present with wheezing or crackles in the lungs. They typically have an increased white blood cell count, and urine, blood plasma and skin zinc levels may (unsurprisingly) be elevated. Chest X-ray findings may also be present.
An interesting feature of metal fume fever involves rapid adaptation to the development of the syndrome following repeated metal oxide exposure. Workers with a history of recurrent metal fume fever often develop a tolerance to the fumes. This tolerance, however, is transient, and only persists through the work week. After a weekend hiatus, the tolerance has usually disappeared. This phenomenon of tolerance is what led to the name "Monday Fever".
In 2006, there were approximately 700 metal fume exposures reported to United States Poison control center. The American Welding Society estimated that 2500 employees in the steel industry develop metal fume fever in the US each year since the majority of the cases are not reported.
Treatment of mild metal fume fever consists of bedrest, hydrate with plenty of water, and symptomatic therapy (e.g. aspirin for headaches) as indicated. In the case of non-allergic acute lung injury in the setting of metal fume fever, a standard or even recommended approach to treatment has not been studied.
A traditional remedy is to consume large quantities of cow's milk, either before or immediately after exposure. However, this advice is challenged by the United Kingdom Health and Safety Executive (the national independent watchdog for work-related health, safety and illness), who write "Don’t believe the stories about drinking milk before welding. It does not prevent you getting metal fume fever."
Prevention of metal fume fever in workers who are at potential risk (such as welders) involves avoidance of direct contact with potentially toxic fumes, improved engineering controls (exhaust ventilation systems), personal protective equipment (respirators), and education of workers regarding the features of the syndrome itself and proactive measures which can be taken to prevent its development.
Particularly for cadmium, the design of the product may be changed so as to eliminate it. NiCd rechargeable batteries are being replaced by NiMH. Cadmium plating is replaced with zinc or nickel. Silver solder alloys now rarely contain it.
- Chastain, Steve (2004). Metal Casting: A Sand Casting Manual for the Small Foundry. p. 8. ISBN 0-9702203-2-4.
- Kaye P, Young H, O'Sullivan I (May 2002). "Metal fume fever: a case report and review of the literature". Emerg Med J 19 (3): 268–9. doi:10.1136/emj.19.3.268. PMC 1725877. PMID 11971851.
- El-Zein M, Malo JL, Infante-Rivard C, Gautrin D (September 2003). "Prevalence and association of welding related systemic and respiratory symptoms in welders". Occup Environ Med 60 (9): 655–61. doi:10.1136/oem.60.9.655. PMC 1740619. PMID 12937186.
- "Chromium and you" (pdf). HSE (UK).
- "Cadmium and you - working with Cadmium - are you at risk?" (pdf). HSE (UK).
- "Medline Medical Encyclopedia: Zinc"
- [Kunimasa K, et al. Chemical Pneumonitis and Acute Lung Injury Caused by Inhalation of Nickel Fumes. Internal Medicine. 50:2035-2038, 2011]
- Cain, J. R.; R. M. Fletcher (2010). "Diagnosing metal fume fever - an integrated approach". Occupational Medicine (London) 60 (5): 398–400. doi:10.1093/occmed/kqq036. PMID 20407044. Retrieved 2010-05-04.
- "Illness caused by welding fume and gases". Health and Safety Executive (UK). Retrieved 9 May 2013.