Recycle and reuse, but is it safe?

I think we can agree that recycling and reusing materials on this planet is a good idea. It is beneficial to get the most out of a material before it ends up in our ever-increasing landfills. What’s interesting is that the material discussed in this article, our landfills will not accept. Recycled tires in the form of tire (rubber) mulch is refused at many landfills because it is known to leach chemicals and heavy metals into the groundwater and natural waterways.

So, what should we do with it? 

Parents and concerned citizens across the United States and Europe are voicing concerns about the use of recycled tires on playgrounds and sports fields. Recently, many countries, states, cities, counties, and school districts have placed bans or restrictions on the use of recycled tires in public areas where children play. Just a few examples are Norway, Sweden, Maine, Vermont, New York City, Boston, Los Angeles Unified School District, and Montgomery County, Maryland. In 2003, the European Union banned the addition of microplastics to the environment, including the use of tire mulch and tire crumb. These restrictions and bans are all due to the safety concerns for humans and the negative impact on our environment. 

When a new tire is made, it contains a host of chemical additives and heavy metals including zinc, lead, cadmium, 6PPD, and polycyclic aromatic hydrocarbons (PAHs). As a tire breaks down, these chemicals and heavy metals are released into the environment. When used tires remain whole, that is one thing, but shredded tires (rubber mulch) are especially likely to leach toxins given the large increase in exposed surface area. The compound 6PPD-quinone is a byproduct of 6DDP and is released as tires degrade. This is a highly toxic compound and is known to kill fish, capable of killing them within hours of exposure to contaminated stormwater runoff.

Research by Northeastern University in 2026 showed that sunlight, heat, and water cause the rubber in tires to decay, creating a hazardous chemical cocktail. Volatile organic compounds (VOCs) are released into the air from tires and can be inhaled as families spend time at the playground. One way to notice VOCs is the smell. If you are smelling tires at the playground, you are inhaling VOCs, and they are entering your system. Unfortunately, heavy metals cause adverse health effects in humans and the chemical compounds discussed above are known carcinogens.  

What should we do with the millions of used tires produced in our society? Companies that sell tire (rubber) mulch and other recycled tire products have figured out a creative way to reuse tires, keep them out of landfills, and make a profit at the same time.

Manufacturers often rebrand tire mulch as “rubber mulch” as a marketing tactic to make their product more appealing to the general public.

Recycled tire applications vary; some of the material is glued together, making a solid surface that stays in place. But the application of tire mulch is risky because the individual particles travel and spread in all directions, entering into storm drains close to playgrounds and entering precious natural water systems, like the marsh.

As a society, we are all figuring out what to do with our used materials, and we are trying to find the most cost-effective and innovative ways to create our infrastructure. When kids and the environment are involved, I believe we should err on the side of caution. On a hot summer day, in a playground covered in tire mulch, see if you can smell the VOCs being released. Safer alternatives have been used for years, including organic infill such as wood chips and cork, natural grasses, or clean sand.

Consumers should know that spreading this material on their property means the water that comes into contact with it will pick up toxic runoff from the tires, and that this runoff will enter our waterways when it rains.

Do not grow food in the vicinity of rubber mulch because of its toxicity. Chemical leaching occurs as the rubber breaks down or heats up in the sun. Tires leach heavy metals such as zinc, cadmium, and lead, as well as polycyclic aromatic hydrocarbons (PAHs). High levels of zinc and other accumulating compounds from decomposing rubber can stunt or kill plants grown for food. Tires retain heat intensely and can release a strong hydrocarbon odor in warm weather. Rubber mulch can catch fire at high temperatures, releasing toxic smoke and is extremely difficult to put out.