A relatively new type of synthetic turf is raising health and environmental concerns among many people. One of the primary concerns is the ground-up recycled tires that are used as a bed for the synthetic blades, as an integral part of this design that has been soaring in use during the past decade, and which is now used on thousands of fields in the US and elsewhere.
Some evidence so far suggests that there are dozens of synthetic chemicals that may be harmful to people who ingest or inhale them, or who come in contact with them as they get scraped while playing on the turf. Other concerns include bacteria that can grow on the surface, excess heat generated by the artificial surface (with ranges of 140-160 degrees documented), and leachate into soil and groundwater.
The jury is still out on what the degree of risk may be to users of spaces such as athletic fields, parks, and playgrounds. A number of government agencies, researchers, and advocacy groups on all sides of the issue continue to develop information.
In the interim, some cities, universities, school districts, athletic groups, and other organizations have already taken some type of action to restrict installation or use of these fields, or remove them, while others give them the green light.
Jurisdictions in your community may be trying to make a decision on this issue this summer, in order to construct or regulate a surface during the construction and active-play season, or to address the heat issue while the sun is high overhead.
Among the early studies that have looked into chemicals linked to the ground-up rubber (commonly called "crumb rubber"), potentially toxic substances detected include polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), semi- volatile organic compounds, phthalates, latex allergens, carbon disulfide, aluminum, arsenic, nickel, cobalt, zinc, selenium, cadmium, iron, manganese, and lead. In some cases, the calculated risk has been greater than the threshold often used by one agency or another. Two of the studies include:
- "Evaluation of Health Effects of Recycled Waste Tires in Playground and Track Products,"  California Office of Environmental Health Hazard Assessment, January 2007.
- "An Assessment of Chemical Leaching, Releases to Air, and Temperature at Crumb-Rubber Infilled Synthetic Turf Fields," NY State Dept. of Environmental Conservation, May 2009: Report  (at bottom) and fact sheet. 
Given the evidence so far, some jurisdictions are taking precautionary actions. The New York City Dept. of Parks and Recreation says that crumb-rubber surfaces are safe, but it is using another type of synthetic turf in any new construction, and is keeping an eye on existing crumb-rubber fields as they age.
- New York City Department of Health and Mental Hygiene, "Fact Sheet on Synthetic Turf Used in Athletic Fields and Play Areas." 
Based upon testing of a limited number of synthetic turf fields in New Jersey for lead, after state officials accidentally discovered high concentrations on a field, the CDC says there is cause for concern, and developed a number of precautionary steps that should be taken to reduce potential harm.
- CDC Health Advisory, "Potential Exposure to Lead in Artificial Turf: Public Health Issues, Actions, and Recommendations,"  June 18, 2008.
In a July 30, 2008, announcement, the Consumer Product Safety Commission concluded that lead concentrations from synthetic turf fields don't pose a significant risk, even though it found lead in all tested samples, and concluded that exposure to the synthetic grass blades would likely result in transfer to the skin. The agency's conclusion was based on the current CDC standard for lead exposure, which many critics and CDC itself acknowledge isn't protective enough (though the agency says it is stymied  for now in setting a more appropriate standard). The CPSC analysis was based only on the synthetic grass-blade material, not the crumb-tire material. The agency asked for guidelines to be developed to reduce the future use of lead in these fields, and has been asked by CDC to continue investigating the synthetic turf issue.
- CPSC statement, "CPSC Staff Finds Synthetic Turf Fields OK to Install, OK to Play On." 
EPA is working on a scoping survey to determine if a larger study is needed, in response to a 2008 request by Connecticut Attorney General Richard Blumenthal. There is no firm timetable for releasing the results of the scoping survey, according to spokesman Dale Kemery,  202-564-7839.
- "EPA accepts Blumenthal's request to study artificial turf,"  Legal Newsline, May 2, 2008, by Chris Rizo.
The Connecticut-based advocacy group Environment and Human Health, Inc. says the tire crumbs, which are 2-3 inches thick and make up to 90% by weight of the turf surface, expose users to the same chemicals that rubber workers are exposed to, but it acknowledges that the risks borne by artificial turf field users remain largely unknown. That is due in part to the fact that, as EHHI says, the studies conducted so far offer only limited information, and have major data gaps. In its own study released in August 2007, it found 25 chemicals that were released by tire crumbs in a laboratory study that the group says simulated ambient conditions during a Connecticut summer. This compares with the 49 chemicals documented from various tire products in the California Office of Environmental Health Hazard Assessment report noted above.
In response to its studies, EHHI recommends a moratorium on use of this kind of artificial turf until additional studies are done, and that use of existing surfaces should be limited. This approach was driven in part by the group's conclusion that, based on existing evidence, there is a technical possibility that the tire crumbs could cause health effects such as irritation of the respiratory system, eyes, skin and mucous membranes, systemic effects on the liver and kidneys, neurotoxic responses, allergic reactions, cancers, and developmental effects.
- EHHI: "Artificial Turf: Exposures to Ground Up Rubber Tires — Athletic Fields, Playgrounds, Garden Mulch." 
Industry groups generally say that the crumb-tire surface is safe to use, and that there is no evidence indicating that users face significant risk. The Synthetic Turf Council says in a June 3, 2009, statement that the New York Dept. of Environmental Conservation study supports its claims of safety.
- Synthetic Turf Council press release, "New York Studies Validate Safety of Crumb Rubber Infilled Synthetic Turf,"  June 3, 2009.
- Synthetic Turf Council, Government and Agency Position Statements. 
The health and environmental issues involved in deciding whether to use real or fake grass include — in addition to the topics already highlighted — costs, year-round and bad-weather playability, water use, pesticides, fertilizers, chemicals used to maintain synthetic turf, disposal of worn-out synthetic turf, and variability in the composition, weathering, and site location of various tire and grass blade products. All of these issues introduce uncertainties and tradeoffs, and you may want to address them in your coverage.
In addition to the sources already cited, and local contractors, interest groups, and jurisdictions considering synthetic turf fields, other resources include:
- Grassroots Environmental Education. 
- New Yorkers for Parks: Collection of media coverage of parks issues,  some of which address artificial turf (recent synthetic turf links are from Dec. 24 and 26, 2008, April 20, 2008, and Feb. 22 and 29, 2008).
- American Sports Builders Association: Statement on safety of artificial turf. 
- "Synthetic Turf: Health Debate Takes Root,"  by Luz Claudio, Environmental Health Perspectives, March 2008.