Tungsten is a naturally occurring steel-gray to tin-white metal or fine powder that comes from more than 20 different tungsten-bearing minerals. It is used primarily to increase the toughness and strength of steel and to make filaments for electric lighting and electron tubes such as TV and radio tubes.
People can be exposed to tungsten through both natural processes and human industrial activities. Trace amounts are found in seawater, and very small concentrations are present in the atmosphere. Large amounts of dust can be released into the air from industries that make tungsten. People are exposed to it by breathing air that contains tungsten; they can also be exposed by eating food or drinking water contaminated with tungsten.
In terms of industrial activities, eleven facilities throughout the United States use various domestic ores to produce one or more forms of tungsten, including tungsten metal powder, ammonium paratungstate (APT) powder, or tungsten carbide powder.
Little evidence exists on the metabolism of tungsten in humans. Tungsten enters your body primarily through breathing it in or ingesting it. Tungsten appears to leave your body primarily in your urine but also your feces.
Workers exposed to high levels of tungsten dust or vapors can have skin, eye, throat, or nose irritation. Workers who are exposed to tungsten often are exposed to other heavy metals, such as cobalt, that usually are part of the tungsten refining and compounding processes. Over long periods of time, these workers can develop lung problems, such as cough, shortness of breath, or wheezing (hard metal disease). Early research on this respiratory condition attributed these symptoms mostly to cobalt exposure instead of to tungsten exposure. In lab animals, recent research shows that cobalt and tungsten together can cause lung damage.
We do not know about any studies of health problems in people who do not work with tungsten.
Very little research has been done to study whether tungsten can cause cancer in animals or humans. Lab animals that were exposed to high amounts of tungsten and cobalt showed early signs of lung cancer. Studies in human workplaces do not link exposure to tungsten alone with more cancer, but one study linked workplace exposure to dust containing a mixture of tungsten and cobalt with lung cancer.
A study of human cell cultures did find that exposure of these cultures to a combination of tungsten and other metals resulted in some signs of cancer development.
Another study using mice found that tungsten did not increase the incidence of breast cancer significantly, but it did not prevent the development of breast cancer cells when compared with another heavy metal.
We found no reports of any research suggesting that tungsten causes leukemia. In our Churchill County leukemia study we found no significant difference in urine concentrations of tungsten between the comparison group and the children (and their families) who were diagnosed with leukemia.
According to the information currently available to the Centers for Disease Control and Prevention, tungsten has not been tested for its ability to affect reproduction or development.
Is the risk of getting sick higher for people who work with tungsten than for people who just live in the community but do not work with it?
The likelihood of becoming sick from some chemical exposures increases as the amount of the exposure increases; risk may depend on the length of time a person is exposed and the amount of chemical the person is exposed to. Workers are usually exposed to higher amounts and thus may be at increased risk if they do not use the appropriate personal protective equipment.
Exposures in the community, except possibly in cases of fires or spills, are usually much lower than those found in the workplace. However, people in the community may be exposed to tungsten over a long period of time through water or air that has been contaminated. Also, employees that work with tungsten may go home wearing clothing and shoes contaminated with tungsten powder or dust, thus exposing their families to the metal.
No reports currently exist that link tungsten exposure in the general population with health problems.