Wildfires ignite concern - Natural Disasters

Every year in the United States wildfires destroy hundreds of homes and cause millions of dollars in damage. From January through May of this year, for example, 2,702 wildfires scorched 198,228 acres in Florida amidst one of the worst droughts in a century. Although wildfires can actually be good for the environment, helping it to stay healthy and restore itself, they can have harmful human consequences, both directly and indirectly. People in close proximity to a wildfire, such as firefighters, can suffer respiratory problems and burns, and in rare instances are killed. In addition, people living near a fire's burn who are predisposed to environmental health problems such as asthma and emphysema may be affected. Perhaps more importantly for those living downwind, forest fire smoke contains many contaminants that in the long term can, depending on the length of the exposure, produce both acute and chronic effects in humans.

Wildfires are characterized as brush and forest fires that commonly happen in relatively undeveloped areas. But as Craig Allen, a research ecologist with the U.S. Geological Survey in Los Alamos, New Mexico, points out, "More and more people are living in what were once remote areas, and that's putting them closer to woodlands and the threat of wildfires."

According to a 1994 scientific study prepared for the Fire and Aviation Management division of the U.S. Department of Agriculture Forest Service, contaminants of forest fire smoke can include carbon monoxide, hydrocarbons, benzo[a]pyrene, nitrogen oxides, volatile oxygenated organic compounds, acids, ketones, alcohols, and aldehydes, among other chemicals. Chronic exposure can lead to allergies, bronchitis, and emphysema, while acute exposure can cause impaired judgment, eye and respiratory irritation, and even death. But although some gases commonly released in burning, such as methane and ethylene, have been shown to be carcinogenic in tests on laboratory animals, no scientific evidence exists to show that wildfires can increase these gases to dangerous levels in the environment.

In addition to their human health effects and obvious damage to the landscapes they burn, wildfires can have other unwelcome environmental effects as well. They affect water quality by destroying vegetation and dead plant matter that slows stormwater runoff; runoff and erosion can increase by an order of magnitude after a wildfire. The extra sediment and ash can also affect aquatic habitats and occasionally kill fish by cutting off the oxygen supply. Furthermore, the threat exists that fire fighting can stress smaller water and power utilities to the point that community drinking water supplies could be adversely affected.

Concerns about water quality have also been raised in connection with the chemicals used to fight and control fires, including fire retardants (composed of ammonium salts, thickeners, corrosion inhibitors, and coloring agents) and fire-suppressant foams (composed of surfactants, stabilizers, and solvents). Between 1994 and 1997 alone, U.S. fire fighting operations used more than 92 million gallons of these chemicals.

"These chemicals have been used in environmentally sensitive areas, so we have done research to determine their impact on plant and animal life," says Susan Finger, an ecotoxicologist and program coordinator for the Columbia Environmental Research Center in Missouri. She says, "Although no effects associated with fire chemical application and exposure were apparent on terrestrial organisms [including humans], potential adverse effects were identified for some of these chemicals in aquatic ecosystems." Finger explains that the introduction of some of these chemicals during a critical time in the life stage of an endangered salmon population, for example, could result in high incidence of mortality or even, potentially, elimination of the population from a localized area. "For this reason," she says, "caution is encouraged when using these chemicals in and around aquatic environments."

In 1995, the federal government established a national fire policy. The policy addresses how resources and personnel can be better used to control fires and recognizes the importance of further research to understand fires and their ecologic significance. In a December 1995 memorandum, the secretaries of agriculture and the interior wrote, "The philosophy, as well as the specific policies and recommendations, of the report continues to move our approach to wildland fire management beyond the traditional realms of fire suppression by further integrating fire into the management of our lands and resources in an ongoing and systematic manner, consistent with public health and environmental quality considerations."

COPYRIGHT 2001 National Institute of Environmental Health Sciences
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