Infill for Artificial Grass - The crumb rubber alternative

There are a variety of artificial grass infill products. Examples include sand, crumb rubber, sand + crumb rubber, acrylic coated sand, and elastomerically coated (rubber coated) sands. That drawing the most attention is Crumb rubber - because of its popular use in sporting application and the potential health hazards/concerns.

Crumb rubber is produced by grinding scrap tires and is used as a common "infill" material for synthetic turf fields.  It provides cushioning and helps to hold the artificial grass down and keeps synthetic grass fibers upright.Wikipedia defines crumb rubber as “a term usually applied to recycled rubber from automotive and truck scrap tires". During the recycling process steel and fluff is removed leaving tire rubber with a granular consistency. Continued processing with a granulator and/or cracker mill, possibly with the aid of cryogenics, reduces the size of the particles further. The particles are sized and classified based on various criteria including color (black only or black and white).


Pros:

• Provides resiliency to the artificial grass
• Provides UV protection
• According to the EPA, crumb rubber in-fill can be used as ground cover under playground equipment and “possesses high impact attenuation/ability to absorb the energy from falling children and objects.
• Does not represent a significant source of lead exposure
• No significant threat from chemicals leaching into surface water and groundwater. While some chemicals can be released from crumb rubber over time, they are in small concentrations and are reduced by absorption, degradation and dilution -- resulting in no significant impact on groundwater or surface water (May 29, 2009 New York State Department of Environmental Conservation and the Department of Health).
• Provides cushion for the players on artificial grass sports fields while keeping a significant number of scrap tires out of our nation's landfills
• Provides a softer playing surface, absorbs the impact of falls
• New York State Department of Environmental Conservation concluded that “crumb rubber material used in synthetic turf fields poses no significant environmental threat to air or water quality and poses no significant health concerns.”
• Better irrigation and stability than sand infill. Granules of sand migrate towards the base of the turf system, causing the surface to become more compact.

Cons:

• Heat Stress - Surface temperatures on crumb-rubber infilled synthetic turf fields can reach levels of discomfort and may contribute to heat stress. Water can be applied to synthetic turf to reduce the surface temperatures on warm days.
• Infection - Skin cuts and abrasions that may result from contact with athletic fields (natural and synthetic turf) are susceptible to infection.
• Chemicals - Based on the review of research studies and reports, certain chemicals have been identified in crumb rubber. These include small amounts of polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs) and heavy metals such as zinc, iron, manganese and lead.
• Although the potential for significant exposure to the chemicals in crumb rubber is very low, there are three possible ways for people to have contact with these chemicals on artificial turf fields:
• Accidentally ingesting small amounts of crumb rubber by putting fingers in the mouth or not washing hands before eating after playing on the fields
• Breathing in dust and vapors while playing on the fields. Crumb rubber may become dust as it wears and the rubber may give off some vapors.
• Direct skin contact with the crumb rubber.

There has also been controversy over the declaration by the CPSC regarding the safety of crumb rubber infills. Below is an excerpt from Attorney General Richard Blumenthal's letter challenging the CPSC report in August of 2008:

"....This report and release are as deceptive as some of the advertising and marketing of consumer products prosecuted by the Federal Trade Commission and state attorneys general.... There is a clear and present danger that municipal and state decision makers — as well as parents and citizens — will rely on this unconscionably deficient report. It is replete with unsound scientific methodology and conclusions, and unreliable findings. It may lead to unsupportable and unwise commitments by towns and cities or their boards of education to build or replace athletic fields... I have personally reached no conclusion on the safety or health issues concerning artificial turf, because no complete or comprehensive study has been done. This one, far from being complete or comprehensive, is profoundly misleading and misguided and may lead to bad policy-making... The CPSC review of artificial turf safety focused entirely on the issue of lead contamination from artificial blades of grass. While this one issue is important, it is neither the sole nor the most significant issue. There is no indication that CPSC staff considered the transferability or emission — especially at high temperatures — of toxic chemicals from the crumb rubber used at the base of artificial turf. This crumb rubber is usually made from recycled tires, containing chemicals — including benthothiazole, butyplated hydroxyanisole and phthalates — that may be toxic or carcinogenic under some circumstances.... Similarly, there is no indication that CPSC considered other important risks, some presented or aggravated by very high temperatures in the summer sun, and exposure to serious infection caused by the more extensive skin burns and abrasions created by falls on this material.... Continued public dissemination of this misleading and deceptive material might well constitute a violation of our consumer protection laws if done by a company selling this product. The CPSC’s distributing it — and vouching for its accuracy — constitutes a violation of its public trust.”


It is because of these concerns that Purchase Green recommends alternatives to crumb rubber for safe and effective artificial grass infills.