Burning rubber is highly toxic. This combustion process, which occurs in scenarios like tire fires and waste burning, releases a complex mixture of harmful gases and fine particulate matter into the atmosphere. When rubber, especially vehicle tires, is exposed to high heat, a chemical breakdown occurs. This breakdown releases chemical components that pose significant risks to human health and the environment.
What Happens When Rubber Burns?
When rubber is heated, especially when oxygen is limited, it undergoes thermal decomposition or pyrolysis. This chemical breakdown shatters the large polymer chains into smaller, volatile molecules. The most visible consequence is the production of extremely dense, black smoke.
This thick smoke is a complex mixture of gases and fine soot, or particulate matter, which is easily inhaled. The burning process releases high concentrations of basic asphyxiants, such as carbon monoxide, a colorless and odorless gas that interferes with the blood’s ability to carry oxygen. The smoke also often contains hydrogen cyanide, a highly toxic gas that can rapidly cause harm.
The intense heat of a rubber fire causes the material to melt and flow, making the fire notoriously difficult to extinguish and prolonging the release of these toxic products.
Hazardous Chemical Emissions
The danger of burning rubber lies in the cocktail of highly toxic, complex chemicals released beyond the immediate smoke and basic gases. Synthetic rubber, particularly in tires, contains various additives and compounds that become airborne upon combustion. These releases include complex Volatile Organic Compounds (VOCs), such as benzene, toluene, and styrene.
Sulfur used in the vulcanization process is released as sulfur dioxide, a pungent and irritating gas. Combustion also generates Polycyclic Aromatic Hydrocarbons (PAHs), which include powerful carcinogens. High temperatures lead to the formation of persistent environmental pollutants, specifically dioxins and furans, which bioaccumulate in the food chain.
Burning rubber also vaporizes heavy metals incorporated as additives or fillers, including zinc, lead, cadmium, and mercury. These metals are released as microscopic particles in the smoke. Since heavy metals do not break down, they represent a systemic, long-term contamination risk.
Acute and Long-Term Health Risks
The health consequences of inhaling rubber smoke are immediate, but prolonged exposure can also lead to chronic diseases. Acute exposure causes rapid and severe irritation of the respiratory system, eyes, and mucous membranes. Symptoms include persistent coughing, wheezing, throat discomfort, and difficulty breathing, especially for individuals with asthma.
Inhaling particulate matter and toxic gases can cause systemic effects, such as headaches, dizziness, and nausea. Ultrafine soot particles penetrate deep into the lungs, exacerbating conditions like bronchitis and potentially causing lung damage. High concentrations of asphyxiants like carbon monoxide and hydrogen cyanide can quickly overwhelm the body, leading to life-threatening conditions.
Long-term exposure shifts the risks toward chronic and potentially fatal diseases due to known carcinogens. Chemicals such as benzene, PAHs, and dioxins are linked to an increased risk of various cancers. Heavy metals released in the smoke, including lead and cadmium, accumulate in body tissues and organs, causing systemic damage, including neurological and cardiovascular issues.