As July 4th approaches, Americans look to the skies. Throughout the
country, fireworks will be launched in celebration of the nation's
independence. But what goes up must come down. Reporter Eric Libby
looks at the environmental issues surrounding fireworks, and efforts to
develop "greener" pyrotechnics.
Take a group of reactive
chemicals, shoot them high into the air, and watch them explode in a
very loud, very smoky, and very hot spectacle. This sounds like the
exact opposite of an environmentally friendly, or green, activity. So
researchers are actively assessing the impact of fireworks and working
to make them safer for the environment.
Among the chemicals
used in fireworks, perchlorates have drawn attention. These compounds
provide the oxygen that fuels the explosion. Hydrogeologist David
Jewett of the Environmental Protection Agency points to an EPA study
measuring perchlorates in an Oklahoma lake after fireworks displays
from 2004 to 2006. "They saw a peak in perchlorate concentrations
within 12 or 14 hours after the fireworks display," says Jewett. "But
then those concentrations decreased back to background levels over a
time period of 20 to 80 days."
Studies have linked perchlorates
to impaired thyroid function. While Julie Heckman, executive director
of the American Pyrotechnics Association, acknowledges the potential
health risks of perchlorates, she says their use in fireworks does not
pose a danger to the public. "The position of the fireworks industry,"
Heckman explains, "is [that] the amount of pyrotechnic composition
containing perchlorate is pretty nominal in terms of what other
industries use or discharge. Look at the military, [which is the]
biggest contributor," she adds.
Julie Heckman notes that U.S.
government regulations prohibit fireworks from containing even
more-toxic substances such as lead and arsenic. Another concern is the
use of so-called heavy metals to give fireworks their colors. In
particular, barium - which is responsible for the color green - is
extremely poisonous in some forms. Mike Hiskey describes how his
pyrotechnics company, DMD Systems, is addressing these concerns. "We
base all our mixes on nitrocellulose, which burns very cleanly, with
basically no smoke, (in)to carbon dioxide, water, and nitrogen. We can
reduce the amount of heavy metals in there by quite a bit, like almost
an order of magnitude," Hiskey adds. "In addition to that, all of our
outdoor pyro contains no perchlorate."
Hiskey says there is
growing interest in green fireworks, especially from indoor concert
promoters and the Disney Company, one of the world's largest users of
fireworks. Scientists at Germany's Ludwig Maximilian University of
Munich are searching for ways to completely replace barium in
fireworks. Graduate student Karina Tarantik says it's difficult to
produce the color green with safer ingredients like copper compounds.
"If
chlorine combines with copper you get blue color and no green. Or if
the temperature is too high of the combustion you get more red or
yellow flame color. So, [it is] quite difficult," she cautions.
Tarantik
says the hardest color to make "green" is, in fact, green. Thankfully,
the most important colors on the 4th of July are red, white, and blue.
