What studies have found
Researchers use 2 main types of studies to try to figure out
if something causes cancer:
-
Lab studies (studies done using lab animals or
cells in lab dishes)
-
Studies in people
Exposure to formaldehyde has been shown to cause cancer in
lab animals. Exposure to relatively high amounts of
formaldehyde in medical and other workplaces has been linked
to some types of cancer in humans, but the effect of
exposure to small amounts is less clear.
Studies in the lab
In rats, inhaled formaldehyde has been linked to cancers
inside the nose and to leukemia. Formaldehyde given in
drinking water has been linked with an increase in tumors in
the stomach and intestines.
Applying formaldehyde to the skin of lab animals has also
been linked to quicker development of cancers caused by
other chemicals.
Studies in people
Some, but not all, studies of people exposed to formaldehyde
in the workplace have reported a link between formaldehyde
exposure and cancer
of the nasopharynx (the upper part of the throat, behind
the nose). These studies looked at people who work in places
that use or make formaldehyde and formaldehyde resins, as
well as at people who work as embalmers.
Studies of people exposed to formaldehyde at work have also
found a possible link to cancer
of the nasal sinuses.
Several studies have found that embalmers and medical
professionals who use formaldehyde have an increased risk
of leukemia,
particularly myeloid leukemia. Some studies of industrial
workers exposed to formaldehyde have also found increased
risks of leukemia, but not all studies have shown an
increased risk. One study found that workers exposed to
formaldehyde had higher than normal levels of chromosome
changes in early forms of white blood cells in their bone
marrow. This finding supports the possible link between
formaldehyde exposure and leukemia.
Studies looking at possible links between workplace exposure
to formaldehyde and other types of cancer have not found a
consistent link.
What expert agencies say
Several national and international agencies study different
substances in the environment to determine if they can cause
cancer. (A substance that causes cancer or helps cancer grow
is called a carcinogen.) The
American Cancer Society looks to these organizations to
evaluate the risks based on evidence from lab, animal, and
human research studies.
Based on the available evidence, some of these expert
agencies have evaluated the cancer-causing potential of
formaldehyde.
The International
Agency for Research on Cancer (IARC) is part of the
World Health Organization (WHO). One of its major goals is
to identify causes of cancer. IARC has concluded that
formaldehyde is "carcinogenic to humans" based on sufficient
evidence it can cause nasopharyngeal cancer and leukemia.
The US National
Toxicology Program (NTP) is formed from parts of
several different US government agencies, including the
National Institutes of Health (NIH), the Centers for Disease
Control and Prevention (CDC), and the Food and Drug
Administration (FDA). The NTP lists formaldehyde as "known
to be a human carcinogen."
The US Environmental
Protection Agency (EPA) maintains the Integrated
Risk Information System (IRIS), an electronic database that
contains information on human health effects from exposure
to various substances in the environment. The EPA has
classified formaldehyde as a "probable human carcinogen." |
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