Hard metal lung disease

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at November 28, 2016
StartDiseasesHard metal lung disease

Hard metal lung disease usually affects workers in the metal industries. The symptoms are similar to other lung diseases. Difficulty breathing is among the most common symptoms of this disorder. There is no cure, and the prognosis for patients is poor.


Definition & Facts

Hard metal lung disease is an interstitial lung disease with pulmonary fibrosis. Most cases are related to occupational hazards; thus it is an occupational lung disease. It was first studied in the 1940s through the 1960s as many workers became ill with breathing problems. Since there was little regulation or safety measures taken at that time, the incidence of the disease was much higher than it is today.

Nevertheless, workers in some industries are still exposed to tungsten carbide and cobalt in both dust and aerosol forms. These can settle into the lungs, causing scars and thickened tissues which can then result in the reduced circulation of oxygen in the body. 

Symptoms & Complaints

There are many signs and symptoms of hard metal lung disease. Because it is a lower respiratory disease, patients will have decreased lung function and the ability to breathe may become limited.

The patient will likely have a tightening feeling in the chest and may have trouble breathing, especially when trying to take deep breaths. This may be accompanied by coughing and shortness of breath, even while resting.

Some patients may experience clubbing, a widening of the tips of the fingers or toes. They may also experience muscle aches and joint aches throughout the body.

The patient is likely to fatigue easily because of poor oxygen circulation in the body. The cough often produces a thick sputum, and the patient often loses weight without explanation.

Once the disease is suspected and X-rays are taken, the lungs are likely to show signs of interstitial patterns which suggest fibrosis. The course of the disease can vary. Some individuals may experience sudden, debilitating symptoms while others may have more moderate symptoms.


Hard metal lung disease is generally caused by exposure to hard metal dust, usually as part of a job in the type of industry that uses these products. Tungsten carbide and cobalt are two of the most potentially hazardous materials that workers may be exposed to.

The amount of time a person worked around the hard metals does not seem to matter. Even those who worked in the industry for short periods of time can develop hard metal lung disease while some who were exposed during their entire adult careers do not develop it. It is believed that some people are simply more sensitive to the metal particles than others.

The hard metal dusts settle into the lungs, causing fibrosis. This causes scars and the thickening of tissues around and between the air sacs in the lungs. This damage to the lungs does not allow oxygen to pass through very easily. Therefore, one's body does not have oxygen circulating as efficiently as a person who does not have this disease. The lack of oxygen can cause many complications and symptoms of hard metal lung disease.

Diagnosis & Tests

Diagnosis of hard metal lung disease is usually straightforward. Work history will usually give the most relevant information to the doctor because if an individual worked around the hard metals and has the obvious symptoms of the disease, then he or she is likely to be afflicted by hard metal lung disease.

If symptoms are present, a doctor will perform a complete physical examination which can include radiographic studies to be completed. If hard metal disease is present, the pictures will show interstitial patterns indicative of fibrosis of the lungs.

At this point, a definitive test, a lung biopsy, will be done. The biopsy will take a sample of the patient’s lung tissue. A patient with hard metal lung disease will show the presence of tungsten carbide in the biopsied cells. The biopsy will also likely show the presence of multinucleated giant cells that have engulfed surrounding cells.

Treatment & Therapy

There is no cure for hard metal lung disease. The patient who has contracted the disease often has a poor prognosis. The patient may be treated with corticosteroids to reduce inflammation. This may help alleviate some symptoms for a short period, and it may slow the progression of the disease for a period. However, it does not reverse the course of the disease.

Additionally, oxygen therapy is often indicated for patients with hard metal lung disease. Again, this does not cure the disease, but it can help the patient to get more oxygen for each breath that they take. It may also help to prevent some complications of low blood oxygen levels, reduce blood pressure, and make sleeping easier for the patient.

Some patients may receive pulmonary rehabilitation that may help them with appropriate physical exercises they can do, teach them breathing exercises, give nutritional counseling, and provide other counseling and education about the disease.

The final option for some patients may be a lung transplant which can improve quality of life but involves the potential of serious complications such as rejection and infection. In many cases, though, there is little that can be done, and the patient is simply made to feel as comfortable as possible for the duration of the disease.

Prevention & Prophylaxis

Prevention of hard metal lung disease requires individuals to exercise caution when there is the potential of exposure to hard metal dust. For those who work in such industries, prevention may involve wearing airtight respirators when one is working in areas that contain the hard metal dust.

In the United States, the government, through the Occupational Health and Safety Association (OSHA) has set limits to the amount of hard metal that can be present in the air. It is important that these standards are kept and monitored.

In addition, it is important to avoid even skin contact with cobalt because this can also cause problems. Individuals who work in industries that involve exposure to metals need to be aware of the risks and take care to avoid them at all costs.