Dioxins are a byproduct of certain manufacturing
processes, such as herbicide production and paper
bleaching. They can be released into the air from
waste burning and wildres.
Perchlorate is a colorless salt manufactured and
used as an industrial chemical to make rockets,
explosives, and reworks, which can be found in
some groundwater.
Per- and polyuoroalkyl substances (PFAS) are a
large group of chemicals used widely in industrial
applications, such as reghting foam, nonstick pans,
paper, and textile coatings.
Phthalates are a large group of compounds used
as liquid plasticizers. They are found in hundreds of
products including some food packaging, cosmetics,
fragrances, children’s toys, and medical device tubing.
Cosmetics that may contain phthalates include nail polish,
hair spray, aftershave lotion, cleanser, and shampoo.
Phytoestrogens are naturally occurring substances
with hormone-like activity found in some plants; they
may have a similar eect to estrogen produced by the
body. Soy foods, for example, contain phytoestrogens.
Polybrominated diphenyl ethers (PBDE) are used to
make ame retardants for products such as furniture
foam and carpet.
Polychlorinated biphenyls (PCBs) were used to
make electrical equipment, such as transformers, and
are in hydraulic uids, heat transfer uids, lubricants,
and plasticizers. PCBs were mass-produced globally
until they were banned in 1979.
Triclosan is an ingredient that was previously added
to some antimicrobial and personal care products, like
liquid body wash and soaps.
National Institute of Environmental Health Sciences
National Institute of Environmental Health Sciences
What have scientists determined?
An in
dependent panel of scientic experts convened
by NIEHS and the National Toxicology Program (NTP)
concluded that there is “credible evidence” that very
small amounts of some hormone-like chemicals harmed
the organs and bodily functions of test animals.
2
This report is foundational to ongoing research.
In addition, both the Endocrine Society and the
European Society of Endocrinology have highlighted
“widespread scientic evidence” that exposure to
endocrine-disrupting chemicals is harmful to human,
animal, and ecological health.
3
Thus, it is important
to minimize exposures, identify new EDCs as they
emerge, and understand underlying mechanisms to
develop interventions.
How do they aect a body?
Researchers have gained insight into how endocrine
disruptors inuence the endocrine system and alter
hormonal functions. Given the variety of chemicals,
it is not surprising that they can act in various ways
in dierent parts of the body. Researchers have
discovered that endocrine disruptors can:
• Mimic, or partly mimic, naturally occurring
hormones in the body like estrogens (female sex
hormones), androgens (male sex hormones),
and thyroid hormones, potentially leading to
overstimulation.
• Bind to a receptor within a cell, like a key within a
lock, and block the naturally occurring hormone
from performing. The normal signal then fails to
occur, and the body does not respond properly.
Examples of chemicals that block hormones are
anti-estrogens and anti-androgens.
• Interfere or block the way natural hormones, or
their receptors, are made or handled in the body, for
example, by altering their metabolism in the liver.