Dioxin Makes the List of Known Carcinogens
Dioxin Makes the List of Known Carcinogens
Updated 5:41 PM ET January 19, 2001
NEW YORK (Reuters Health) - The government has placed a type of dioxin
called TCDD on the list of substances that are known carcinogens.
The announcement was made by the National Toxicology Program on Friday and
is based on "sufficient evidence of carcinogenicity from studies in
humans,"
according to a statement released by the National Institute of Environmental
Health Sciences, a branch of the National Institutes of Health (NIH). It is
now clear that there is "a causal relationship between exposure to TCDD
and
human cancer," the group said.
The term "dioxins" refers to a group of compounds that share a
certain
chemical structure and biological characteristic. Sometimes the term dioxin
is also used to refer to the most well-studied and one of the most toxic
dioxins, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), according to the
Environmental Protection Agency (EPA).
"TCDD is not deliberately produced today but has been found as a
contaminant
in some herbicides and pesticides, and is formed as an inadvertent
by-product of incineration of waste," according to the NIH.
The chemical was scheduled to appear in the Ninth Report on Carcinogens,
released earlier this year, however the addition of TCDD was held up due to
litigation.
Dioxin can cause "skin rashes, skin discoloration, excessive body hair
and
possibly mild liver damage," according to the EPA.
"Because dioxins exist throughout the environment, almost every living
creature including humans has been exposed to dioxins," according to the
EPA. "The health effects associated with dioxins depend on a variety of
factors including: the level of exposure, when someone was exposed, and how
long and how often. Because dioxins are so widespread, we all have some
dioxins in our bodies."
Dioxin came to public attention as the contaminant in Agent Orange, a
controversial herbicide used by US forces in Vietnam. In 1983, the EPA
forced the evacuation and demolition of the entire town of Times Beach,
Missouri, after the discovery of dioxin contamination on city streets.
Over the past 5 years, the EPA has imposed regulations on major dioxin
emitters, including municipal waste combustors, medical waste incinerators,
hazardous waste incinerators, cement kilns that burn hazardous waste, pulp
and paper operations, and sources of PCBs.
One source likely to be targeted in the future is uncontrolled residential
waste burning, such as burning trash in backyards, particularly in rural
areas. The agency also is discussing the possible regulation of other
sources such as sludge disposal from privately owned waste-treatment
facilities and the regulation of other air sources of pollution.
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