SACRAMENTO — The U.S. Environmental Protection Agency has terminated its longtime campaign to promote the use of recycled tires on artificial turf fields and playgrounds, amid growing concern from critics in California and elsewhere who fear the material poses a health risk to people.

Millions of children and athletes across the nation play on surfaces that contain rubber from scrap tires. The rubber is transformed into colorful soft landing mats beneath playground equipment or shredded to act as a replacement for wood bark at schools and parks. Ground up further, it makes up the tiny black pebbles that give resiliency to artificial turf.

But environmental groups and health advocates say the EPA failed to thoroughly study the health effects of the so-called “crumb rubber” because the agency was vested in promoting recycling of the material as a solution to the nation’s growing stockpile of scrap tires. They fear the crumb rubber infill, used in artificial fields since the 1990s, has contributed to cancer cases in 126 soccer, field hockey and football players across the nation.

“The EPA made a mistake in promoting this. That’s my personal view,” said Suzanne Wuerthele, a former EPA toxicologist who is now retired. “This was a serious no-brainer. You take something with all kinds of hazardous materials and make it something kids play on? It seems like a dumb idea.”

Concerns about the possible link to cancer prompted a California lawmaker to call for a moratorium on the installation of crumb-rubber synthetic fields and playgrounds until the state can thoroughly study its health effects.

“We have a responsibility to ensure that our children aren’t being harmed by materials used on these fields and in their playgrounds,” said state Sen. Jerry Hill, D-San Mateo, who introduced SB47 in December to require California to study at least 20 turf fields and playgrounds and halt new ones from being constructed with the material for two years until research is complete. “Nearly all of the existing studies cite the need for additional research about whether there is a risk. The tests have never been conclusive, and there is a greater increase in the use of tire crumb.”

Groups concerned with the material say the studies done to date — including a 2009 EPA study — have looked only at a limited number of toxics at a handful of fields, and they are calling for additional research.

“The common sense concern is that this is just chopped up hazardous waste,” said Jeff Ruch, executive director of the Public Employees for Environmental Responsibility, a national nonprofit that has fought the EPA since 2009 over the federal agency’s endorsement of ground tires in playgrounds and sports fields.

Industry groups say dozens of studies have validated the safety of synthetic turf, which appeared on the market in the 1960s and included crumb rubber or other infill material, such as sand, in the 1990s to enhance the product. Today, there are more than 11,000 turf sports fields across the country, according to the trade group the Synthetic Turf Council. Each field uses 20,000 to 40,000 scrap tires, according to various studies and industry groups.

“There are always things you can research more,” said Dan Zielinski, spokesman for the Rubber Manufacturers Association. “But, given the body of research already done, had there been means for concern, I think we would have seen it.”

126 athletes

University of Washington assistant soccer coach Amy Griffin points to her list of cancer-stricken athletes as reason enough for concern. Eighty-two of the 126 athletes on her list are soccer goalies, players who were constantly diving into the synthetic turf.

“Goalkeepers are in this stuff all the time,” Griffin said. “Generally, during training, there are plenty of drills that you dive and save ball after ball after ball. You never really leave the ground.”

At first, in 2009, Griffin said she thought it was a strange and sad coincidence that she knew two goalies diagnosed with cancer. Then Griffin heard of more players.

One goalie with cancer told her she couldn’t help but think it had something to do with the little rubber pellets all over the turf field, the ones that would find their way into players’ clothes, eyes, nose and mouth throughout games and practices. The ones tracked into homes and found at the bottom of showers when players rinsed off.

Griffin said she found there was little conclusive research on the health effects of the recycled tire pieces players often called “turf bugs.” Since sharing her suspicions publicly, she said her phone has been ringing steadily and her list of athletes with cancer has grown.

“I was ready for people to call me and say I’m crazy, and instead people called and said, 'I’ve always wondered what’s in that stuff,’” Griffin said.

EPA’s turf plan

EPA efforts to promote recycled tires on athletic surfaces date back to a 1991 agency report on various ways to reduce the nation’s scrap tire stockpile. The report said the tire piles posed a health risk because they were ideal breeding grounds for mosquitoes, which can spread diseases, and provided potential fuel for hazardous and toxic fires. Using recycled tire material on playgrounds and sports fields, among other possibilities, had potential, the report noted.

By 2003, the agency had partnered with environmental agencies in California and other states and with rubber manufacturers to create the Scrap Tire Workgroup, which promoted the use of recycled tires — including in playgrounds and artificial turf — and developed strategies to counter concerns about the toxicity and volatility of the material.

One strategy outlined in the Workgroup’s 2007 marketing plan involved designating the EPA as the chief marketer to persistently promote the use of ground rubber while at the same time compiling and producing studies to respond to health and safety concerns over the material. Another strategy involved encouraging states to provide subsidies to cities and school districts that installed recycled tire material on playgrounds and athletic fields.

Indeed, millions of dollars in subsidies have been handed out. In California, part of the $1.75 fee added to each new tire purchase pays for annual grants, such as $47,000 for San Jose Unified School District to buy crumb rubber to install turf fields at two elementary schools and $24,000 to San Francisco Recreation and Parks Department to help cover the cost of rubber infill for synthetic sports fields at Ocean View Playground.

Money for new turf

Between 2005 and 2014, the California Department of Resources Recycling and Recovery (CalRecycle) awarded $21.4 million in tire recycling grants, mostly to cities and school districts wanting to use recycled tires on playgrounds and in new turf fields.

Of those, 22 grants worth a total of $2.3 million helped schools and park districts buy 7.5 million pounds of recycled rubber for synthetic turf fields, which is the equivalent of 623,000 passenger car tires, said CalRecycle spokesman Mark Oldfield.

Next month, more than $800,000 in new grants is scheduled to be awarded to cities, schools, state agencies and Indian tribes, Oldfield said.

During the time the EPA was involved in the Scrap Tire Workgroup, the agency issued a 2009 study on the health effects of crumb rubber, saying it found low levels of concern even though it identified 30 compounds found in tires, including known carcinogens and toxic substances such as arsenic, lead and cadmium. But in 2013, the EPA backed off that earlier statement. The agency said its 2009 study — often cited by industry groups to validate the safety of crumb rubber — was limited in scope and that no conclusions should be drawn by it.

Now, the EPA is further distancing itself from the crumb rubber controversy. Laura Allen, spokeswoman for the EPA, said the agency is no longer affiliated with the Workgroup and has no current initiatives to reduce tires in landfills.

“The agency ended staff participation in the independent Workgroup in May 2014, and closed out administrative participation at the end of the year,” Allen wrote in an e-mail to The Chronicle.

When asked if health concerns played a part in the EPA’s decision to withdraw from the group, Allen said only, “There were various factors taken into consideration.”

More tests needed

The agency also says more testing on crumb rubber is needed and that states and local agencies should be responsible for conducting that research.

“The decision to use tire crumb remains a state and local decision,” Allen said. “Our highest priority is protecting public health and the environment, and we will carefully review any new findings or information.”

Retired EPA environmental geologist Mark Schuknecht, who until May 2014 worked as a full-time coordinator for the Scrap Tire Workgroup, said he believes the agency’s decision to disinvest in the group was due to budget cuts, not health concerns with the materials.

Schuknecht said he’s confident the use of scrap tires on playgrounds and sports fields is safe and that future studies would come back the same.

“I was trying hard to keep EPA involved in the Workgroup while I was there and I was successful keeping them involved until I left,” Schuknecht said. “That was my desire. With them involved, it helped encourage work within the group and kept scrap tires on people’s minds. I think it was a positive thing.”

The Workgroup continues to promote the material without the EPA’s involvement. One of its members, the Rubber Manufacturers Association, calls the use of recycled tires across the nation “an environmental success story.” In 2013, 96 percent of scrap tires discarded that year were recycled for various markets. The nation’s scrap tire stockpile dropped from 1 billion in 1990 to 75 million tires in 2013, according to the association.

Putting recycled tires on playgrounds and turf not only cleans up the environment and reduces water use, it provides recreational space that can be used far more often because, unlike real grass, it doesn’t need time to recover, Zielinski said.

'Government failure’

Public health toxicologist David Brown said the government failed the people.

“The studies that have been done are narrow and mostly funded by the industry or waste bureaus trying to get rid of tires,” said Brown, who is the past chief of environmental epidemiology at Connecticut’s Department of Public Health and currently works with the Connecticut-based advocacy group Environmental and Human Health Inc., which opposes the use of recycled tires where children play due to health concerns.

“The objective work that needs to be done hasn’t been done,” Brown said. “I see it as a governmental failure across the board that really we should try to learn from. We should ask the question, 'Who was responsible for determining the safety of these things?’”

In 2009, the Los Angeles Unified School District said due to health concerns it would no longer use recycled tires on its turf fields, opting for alternatives like cork, and removed the used rubber from early education centers. The New York City Department of Parks and Recreation also stopped using recycled tires on newly installed sports fields amid health concerns, instead opting for alternative products.

In San Francisco, the Recreation and Park Department expects to replace grass at the Beach Chalet athletic fields in Golden Gate Park with synthetic turf in November using the recycled rubber Hill’s bill proposes to study.

Sarah Ballard, spokeswoman for the parks department, said alternative products have not been well-vetted and may not hold up as well as the rubber pieces. Ballard said the parks department hopes to pilot the use of alternative products at smaller fields to see how they fare.

Opponents of the synthetic fields at Beach Chalet said they will continue to push for the parks department to use alternative products on the fields instead of recycled tires, such as used shoes, coconut fibers, rice husks or cork.

“We need to step back and study these before we install any more,” said Kathleen McCowin, who was arrested after staging a one-person sit-in at Golden Gate Park to stop construction of the new turf soccer fields. “I wouldn’t have gone to jail for anything less than children’s health. My daughter has played on (turf) fields. I drove her to these fields. I’ve had colleagues who say that’s all that’s left. It’s either play on these toxic turf fields or don’t play.”

Melody Gutierrez is a San Francisco Chronicle staff writer. E-mail: mgutierrez@sfchronicle.com Twitter: @MelodyGutierrez