Rubber Mulch Dangers

Rubber mulch is being used for a wide variety of applications from playground surfaces to flower beds, but the dangers are not commonly known to consumers. Rubber mulch is made from recycled tires. Tires are made from rubber and other toxic additives like latex and zinc. When the rubber begins to break down, it releases these toxic chemicals into the soil and possibly even the water, adversely affecting everything around it.

Rubber tires are typically classified by some states as "hazardous waste." Other states refer to them as "special waste." Many different toxic additives and chemicals are used to produce rubber tires. Among these toxins are cadmium, chromium, aluminum, copper, sulfur and zinc. Bits of the rubber mulch contain small pieces of steel and nylon. Other harmful chemicals found in tires are benzene, phthalates, butylated hydroxyanisole, 3-phenyl and latex.

Using rubber mulch in your flower or vegetable garden is toxic to your plants. Rubber tires can be manufactured with as much as 2 percent zinc content, which can be absorbed into your plants when the rubber starts to break down. Most plants cannot grow in such soil conditions. Toxins from the breakdown of the tires kill not only the plants, but also beneficial insects.

When mulch is heated by the sun, it gives off toxic gases. Two of these gases are VOCs (volatile organic compounds) and PAHs (polyaromatic hydrocarbons). These gases cause irritation and inflammation of the nasal passages and the respiratory system. Toxic gases that are released can also cause depression, headaches, nausea, dizziness and eye and kidney damage. The types of chemicals used to make rubber tires are suspected to be toxic to the developmental, reproductive, endocrine and central nervous systems. Long-term exposure may lead to more serious conditions such as cancer.

There is no doubt that rubber tires are made from toxic substances, therefore rubber mulch will give off these toxins when the tires start to decay. Toxins like maganese, selenium and zinc are then absorbed into the soil and into the plants. In addition to contaminating the soil, these toxins could quite possibly contaminate the ground water as well, although this has not yet been proven.

Another drawback of rubber mulch is the foul odor that is emitted when the mulch gets hot. Rubber mulch can also be a potential fire hazard because it heats up quickly and stays hot to the touch. The temperature of a rubber tire in the sun can exceed 172 degrees F. The heat that is reflected off the hot surface can also increase the risk of heatstroke.