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What's Burning in Your Campfire? Garbage In, Toxics Out

Cadmium dust is carcinogenic to humans and animals. Cadmium is used in batteries and dyes. High levels were detected in the ash from campfires that burned nickel-cadmium batteries and in smaller amounts from campfires that burned a colored cardboard box and alkaline and lithium batteries (figure 12).

[image] Line graph showing that nickel-cadmium batteries release much more cadmium in smoke compared to wood.
Figure 12—Nickel-cadmium batteries, colored cardboard, and alkaline and
lithium batteries left higher levels of cadmium in the ash that did a campfire
that just burned wood. Cadmium dust is carcinogenic to humans and animals.

Although there is only limited evidence that beryllium causes cancer in humans, there is evidence that it causes cancer in animals. Beryllium levels were barely detectable in the ash from camp-fires that just burned wood. High levels of beryllium were detected in the ash of campfires that burned nickel-cadmium, alkaline, and lithium batteries (figure 13).

[image] Line graph showing that nickel-cadmium, alkaline and lithium batteries leave behind much more beryllium in the ash compared to wood.
Figure 13—Ash from a campfire that burned nickel-cadmuim and alkaline
and lithium batteries had high levels of beryllium, which causes cancer in animals.
Beryllium levels were barely detectable in the ash when the campfire just burned wood.

Lead is a suspected carcinogen and may affect the lungs and kidneys. Small amounts are present naturally in certain soils. Lead is used in storage batteries and for pigments in paint. A small amount of lead was detected in the ash from campfires that just burned wood. However, almost 10 times more lead was detected in the ash from the campfire that burned a broken fiberglass spinning rod. Additional garbage items that left elevated amounts of lead in the ash (figure 14) were:

[image] Line graph showing the amount of lead left in the ash comparing different garbage items and wood.
Figure 14—Some garbage items left elevated levels of lead—a suspected
carcinogen—in the ash compared to a campfire that just burned wood.

Exposure to high levels of mercury results in permanent nervous system and kidney damage. Mercury levels were barely detectable in the ash from camp- fires that just burned wood. The only garbage items that left more than three times as much mercury in the ash were cigarette and candy wrappers.


We could find no studies on the contribution of toxic air pollutants from garbage burned in a campfire to short- or long-term health effects on humans or animals. This study shows that even campfires that just burn wood release a significant amount of air pollutants. Adding garbage to the campfire increases many of these air pollutants.

The ash left from a campfire that just burned wood is made up mainly of nontoxic elements. When garbage is burned in the campfire, toxic elements in the ash are greatly increased. Anyone handling the ashes from a campfire should wear gloves to reduce their exposure to toxic materials.

Several factors determine whether exposure to toxic air pollutants and elemental metals will pose health effects and how severe those effects will be. Some factors are: the amount and length of exposure; how it enters the body; and characteristics of individuals, such as age and gender.

This study was performed to simulate a campfire. The amount of pollutant produced by wood fires changes as the fires burn. A study conducted under controlled conditions that took the combustion efficiencies of different fuels into account could produce different results than those of this informal study.

The common-sense summary of the results of this study is: Do not burn garbage in a campfire! Pack it in, pack it out.


I would like to thank Dr. Ron Susott, Ron Babbitt, Sherri Dingley, and Steve Baker of the Rocky Mountain Research Station's fire chemistry project in Missoula, MT, for peer review and for contributing their research knowledge of fire chemistry; Sherri Dingley for collecting and analyzing the gas samples; Tony Ward of the University of Montana's Center for Environmental Health Sciences for his review and expertise with toxins that are hazardous to human health; and Lori Messenger, smokejumper, for her help in building great campfires.


Patnaik, Pradyot. 1999. A comprehensive guide to the hazardous properties of chemical substances, 2d ed. New York: John Wiley and Sons.

Sax, N. Irving; Lewis, Richard J., Sr. 1989. Dangerous properties of industrial materials, 7th ed. New York: Van Nostrand Reinhold. 3,527 p.

Seiler, H. G.; Sigel, H., 1987. Handbook on toxicology of inorganic compounds. New York: Marcel Dekker, Inc. 1,069 p

About the Author

Mary Ann Davies received a bachelor's degree in mechanical engineering with a minor in industrial and management engineering from Montana State University in 1988. She worked in the Pacific Northwest Region as a facility engineer and as a tramway engineer. Mary Ann has worked in fire management as a crewmember and as a crewboss. She worked for 5 years with the Rocky Mountain Research Station in the fire chemistry and fire behavior groups before coming to MTDC in 1999.

Library Card

Davies, Mary Ann. 2004. What's burning in your campfire: garbage in, toxics out. Tech Tip 0423–2327–MTDC. Missoula, MT: U.S. Department of Agriculture, Forest Service, Missoula Technology and Development Center. 8 p.

Describes the results of an informal study during which samples of smoke and ash were collected from two camp- fires that just burned wood and 27 camp- fires that burned specific items of garbage in addition to the wood. Some of the items of garbage included plastic bags, disposable batteries, a fishing rod, a colored cardboard box, and the foil packaging used for freeze-dried foods. Even campfires that just burn wood release a significant amount of air pollutants, but when garbage is added to a campfire, the levels of many harmful air pollutants increase. The ash from a campfire that just burns wood primarily contains materials that are not toxic. When garbage is added to the campfire, increased levels of toxic materials are left in the ash.

Keywords: air quality, ash, batteries, camping, carcinogens, heavy metals, metallic elements, plastic bags, pollutants, recreation management, smoke, toxic substances, trash, wood

Single copies of this document may be ordered from:

USDA Forest Service, MTDC
5785 Hwy. 10 West
Missoula, MT 59808–9361
Phone: 406–329–3978
Fax: 406–329–3719

Electronic copies of MTDC's documents are available on the Internet at:


For further technical information, contact Mary Ann Davies at MTDC.

Phone: 406–329–3981
Fax: 406–329–3719

Forest Service and Bureau of Land Management employees can search a more complete collection of MTDC's documents, videos, and CDs on their internal computer network at:

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