On this day in engineering history, the United States
banned the interstate shipment of existing stocks of bulk fluorocarbons,
chemical compounds that contain carbon-fluorine bonds. These fluorocarbon gases
were used in consumer aerosol products such as hair sprays, deodorants, household
cleaners, and pesticides. In such products, fluorocarbons have since been
replaced by propellant gases and mechanical pumps.
The interstate-shipment ban of April 15, 1979 was one in a
series of steps aimed at phasing out the production and distribution of most
(but not all) fluorocarbons. The prohibition exempted products on store shelves
and in commercial distribution, and did not affect inhalation pharmaceuticals,
electrical cleaning sprays, aircraft maintenance products, and insecticides.
The Scientists Warn
the Politicians
In 1976, the National Science Foundation (NSF) and the
National Academy of Sciences (NAS) warned policymakers about a connection
between fluorocarbons and the depletion of the ozone layer, a gaseous shield
which protects humans, plants and animals from harmful ultraviolet (UV)
radiation. Subsequent research indicated that strong winds carry chemicals such
as chlorofluorocarbons (CFCs) into the Earth's stratosphere, where they break
down and release chlorine. According to the U.S. Environmental Protection Agency
(EPA), "each chlorine atom attacks ozone by joining with and breaking apart as
many as 100,000 ozone molecules during the time it is in the stratosphere."
Fear is Tangible
During the 1970s, Americans became increasingly concerned
about cancer and the chemicals which might cause it. Although environmentalists
warned that the nation's fleet of high-flying aircraft threatened the ozone
layer, the public was slow to appreciate the potential harm posed by nitrogen
oxide (NOx) emissions. Nevertheless, aerosol cans which contained
chlorofluorocarbons (CFCs) provided people with a more tangible sense of
danger, especially for those who worried about increased rates of skin cancer.
In October 1976, Congress passed the Toxic Substance Control
Act, a statute which gave the U.S. Environmental Protection Agency (EPA) broad
regulatory authority over CFCs. Two years later, on October 15, 1978, the EPA and
several other government agencies ordered producers of bulk chlorofluorocarbons
to stop making them for use in aerosol products. Specifically, the actions of
the Interagency Regulatory Liaison Group affected Allied Chemical Corp., DuPont
Co., Kaiser Aluminum and Chemical Corp., Pennwalt Corp., and Racon, Inc.
Resources:
http://www.epa.gov/history/topics/ozone/01.htm
http://www.ciesin.columbia.edu/docs/003-006/003-006.html
www.ifdn.com/teacher/glossary.htm
http://en.wikipedia.org/wiki/Fluorocarbon
http://www.epa.gov/sunwise/kids/kids_ozone.html
Image: http://www.epa.gov/history/topics/ozone/01.htm
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