Health impacts of open burning of used (scrap) tires and potential solutions (science memo)

scraptires.doc30 KB

Health impacts of open burning of used (scrap) tires and potential solutions

What follows is some information about the health effects of emissions from burning piles of used (scrap) tires. I am also including some information about the problem of groundwater contamination that results from burning piles of scrap tires, and potential solutions to the problem of scrap tires.

Recently, the U.S. EPA published the following study: U.S. EPA (October 1997) "Air Emissions from Scrap Tire Combustion." (The study is also available in Spanish: "Emisiones al Aire de la Combustion de Llantas Usadas"). The study shows that emissions from the burning of tires are a serious threat to human health. Specifically, emissions from burning tires are highly mutagenic (more mutagenic than emissions from the burning of all other bulk materials that researchers have tested). Emissions from burning tires contains significant amounts of the following known human carcinogens: benzene, 1,3-butadiene, and benz[a]pyrene. What follows are quotes from the study:

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"Two to three billion scrap tires are in landfills and stockpiles across the United States, and approximately one scrap tire per person is generated every year. Scrap tires represent both a disposal problem and a resource opportunity (e.g., as a fuel and in other applications). Of the many potential negative environmental and health impacts normally associated with scrap tire piles, the present study focuses on (1) examining air emissions related to open tire fires and their potential health impacts, and (2) reporting on emissions data from well designed combustors that have used tires as a fuel. . . .

"Open Tire Fires

"Air emissions from open tire fires have been shown to be more toxic (e.g., mutagenic) than those of a combustor, regardless of the fuel. Open tire fire emissions include "criteria" pollutants, such as particulates, carbon monoxide (CO), sulfur oxides (SO2), oxides of nitrogen (NOx), and volatile organic compounds (VOCs). They also include "non-criteria" hazardous air pollutants (HAPs), such as polynuclear aromatic hydrocarbons (PAHs), dioxins, furans, hydrogen chloride, benzene, polychlorinated biphenyls (PCBs); and metals such as arsenic, cadmium, nickel, zinc, mercury, chromium, and vanadium. Both criteria and HAP emissions from an open tire fire can represent significant acute (short-term) and chronic (long-term) health hazards to firefighters and nearby residents. Depending on the length and degree of exposure, these health effects could include irritation of the skin, eyes, and mucous membranes, respiratory effects, central nervous system depression, and cancer. Firefighters and others working near a large tire fire should be equipped with respirators and dermal protection. Unprotected exposure to the visible smoke plume should be avoided.

"Data from a laboratory test program on uncontrolled burning of tire pieces and ambient monitoring at open tire fires are presented and the emissions are characterized. Mutagenic emission data from open burning of scrap tires are compared to other types of fuel combustion. Open tire fire emissions are estimated to be 16 times more mutagenic than residential wood combustion in a fireplace, and 13,000 times more mutagenic than coal-fired utility emissions with good combustion efficiency and add-on controls.

"A list of 34 target compounds representing the highest potential for inhalation health impacts from open tire fires was developed by analyzing laboratory test data and open tire fire data collected at nine tire fires. The list can be used to design an air monitoring plan in order to evaluate the potential for health risks in future events. Methods for preventing and managing tire fires are presented. Recommendations are presented for storage site design, civilian evacuation, and fire suppression tactics. For example, tire piles should not exceed 6 m (20 ft) in height; maximum outside dimensions should be limited to 76 m (250 ft) by 6 m (20 ft). Interior fire breaks should be at least 18 m (60 ft) wide. Civilians should be evacuated when they may be subject to exposure by the smoke plume. Fire suppression tactics are site and incident-specific and firefighters should have specialized training to deal effectively with them.


"Airborne missions from open tire fires have long been suspected of representing a serious impact to health and the environment. However, due to the lack of sufficient data, it was uncertain as to exactly what was being emitted, how much was being emitted, and how dangerous these emissions were, especially to sensitive individuals (e.g., children and the elderly). In recent years, a number of laboratory and field test programs have been conducted to identify and quantify these emissions. This section summarizes the results of a number of key studies in this area and briefly discusses certain aspects of preventing and managing tire fires.


"A controlled simulation test program designed to identify and quantify organic and inorganic emission products during the simulated open combustion of scrap tires was conducted by EPA (Ryan, 1989) and further documented in an Air and Waste Management Association Paper [(AWMA) Lemieux and Ryan, 1993]. This important study is summarized in detail below. . . .

"The results of the test program are presented in Tables 1 through 4. Table 1 presents an averaging of the three sets of volatile organic sampling train (VOST) samples taken at each run condition, each taken at different periods during the burn. Benzene is emitted in large quantities under both conditions. The majority of the volatile organic emissions are aliphatic-, olefinic-, or acetylenic-substituted aromatics. Cyclic alkanes, alkenes, and dienes were also present. Butadiene, a major constituent of the tire fabrication process was also present. . . .

"PAH emissions data are presented in Table 4. The 16-PAHs include several compounds known to be carcinogenic. In particular, the presence and magnitude of benzo(a)pyrene (BaP) is of major concern. BaP is often a highly-scrutinized compound during evaluations of combustion processes, due to its high cancer potency. . . .

"A separate particulate collection system was used to analyze 17 metals found in combusted-tire ash residues. The results of the metals analysis are presented in Table 6. The only significant metals emissions compared to blank samples were lead and zinc emissions. The authors concluded that both average gaseous concentration and estimated emissions of zinc increase with increasing burn rates.


"In a follow-up study to the 1989 Ryan report, Lemieux and DeMarini (1992) analyzed the air emissions data collected in the laboratory study to evaluate potential health impacts. An experimental technique called bioassay-directed fractionation combined with additional GC/MS analyses was used to evaluate quantity and potency of airborne mutagens from the PICs emitted during open tire burning. It was concluded that: "The mutagenic emission factor for open tire burning is the greatest of any other combustion emission studied previously. For example, it is 3-4 orders of magnitude greater than the mutagenic emission factors for the combustion of oil, coal, or wood in utility boilers" (Lemieux and DeMarini, 1992). A mutagen is defined as a substance that causes mutations. A mutation is a change in the genetic material in a body cell. These mutations can lead to birth defects, miscarriages, or cancer (ATSDR, 1990).

"Mutagens are of concern because "the induction of genetic damage may cause an increased incidence of genetic disease in future generations and contribute to somatic cell diseases, including cancer, in the present generation" (Amdur, 1991). . . . The authors concluded that open burning of tires, wood, and plastic results in exceptionally high
mutagenic emission factors and that "open burning, regardless of the feed stock or fuel,
results in greater mutagenic emission factors than does controlled combustion provided by various types of incinerators or boilers" (Lemieux and DeMarini, 1992). The authors found similar mutagenic emission factors of semi-volatile organics produced by the large (chunk) and small (shred) tire pieces. They also found that the mutagenic emission factors for the particulate organics were much greater than those for organics.

"The report`s final conclusion serves as a potentially serious warning: "Considering the (a) relatively high mutagenic potency of the particulate organics, (b) high mutagenic emission factors, and (c) presence of many mutagens/carcinogens, especially PAHs, in the effluent from the open burning of tires, such burns pose a genuine environmental and health hazard" (Lemieux and DeMarini, 1992)."

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In addition, the study emphasized another impact of burning tires: the release to the ground and groundwater of hazardous substances. What follows is a quote from the study:

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"Other Impacts from Open Tire Burning

"The scope of this report is limited to airborne emissions. However, significant amounts of liquids and solids containing dangerous chemicals can be generated by melting tires. These products can pollute soil, surface water, and ground water and care must be taken to properly manage these impacts as well."

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So, considering that there are millions of scrap tires, and that open burning of used scrap tires is a very bad thing, what can environmentalists suggest we do with these millions of scrap tires?

One of the best solutions I found is to use scrap tires with asphalt to make a more durable highway surface. If you want, we can research this issue further. What follows is an excerpt from an Internet document prepared by a scientist from the University of Missouri:

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"Every year in the United States, 250 million automobile tires are discarded, presenting a serious disposal problem. Scrap tires take up large amounts of space and are difficult to destroy. The unsightly mounds of tires are flammable and release toxic fumes when burned.

" This publication is intended to help Missourians comply with state regulations in reducing accumulations of scrap tires. Some potential uses for scrap tires . . . are provided here. . . .

"Highway applications

"Recycled rubber is used in asphalt overlays on highways. A reclaimed rubber modified asphalt mixture improves stability, durability, reflective crack reduction and oxidation resistance. All of this adds up to a mixture with an indicated service life outlasting our conventional mixes. Construction procedures are similar to typical lay-down operations."