A report on a possible link between a rare brain cancer that killed six professional US baseball players and toxic chemicals in artificial turf is raising a new round of questions over whether synthetic sports fields pose a health threat to athletes and others who use them.
The six athletes, who all died from glioblastoma, played most of their careers with the Philadelphia Phillies, a team that for decades competed on artificial turf in Veterans Stadium, the Philadelphia Inquirer reported.
All artificial turf is made with toxic PFAS compounds and some types are still produced with recycled tires that can contain heavy metals, benzene, volatile organic compounds and other carcinogens, and a growing number of US municipalities and states have banned or proposed banning them.
The Phillies players’ deaths are more evidence that regulators need to prohibit synthetic fields, said Kyla Bennett, a former Environmental Protection Agency (EPA) scientist now with the Public Employees for Environmental Responsibility non-profit.
“There is a high number of Philadelphia Phillies diagnosed with this rare cancer and it looks weird, so that should be a red flag,” said Bennett. “We don’t know what those chemicals are doing to us – what happened to exercising caution when we’re talking about human health?”
However, all brain cancer experts who have spoken with the Guardian or were quoted in previous stories on the Phillies deaths cautioned that it is impossible to prove that the ball players’ cancers were caused by PFAS from the turf.
“The bottom line is anything in the world is possible, but what’s plausible and provable are totally different things,” said Henry Friedman, a neuro-oncologist at Duke University who treated two of the players. “There is no way to now say, ‘If these chemicals are there, they are causing the tumors.’”
The federal government estimates about 12,000 synthetic turf fields exist in the US, and at least 1,200 more are installed annually. Only five professional baseball teams still use synthetic fields, the Inquirer reported.
Several layers comprise synthetic fields: plastic grass blades, plastic backing that holds the blades in place and infill that weighs down the turf. Until recently, infill was always made with recycled rubber tires called crumb rubber, which EPA testing has found contains high levels of dangerous chemicals.
Recent independent testing of multiple artificial fields has found the presence of highly toxic PFAS compounds like 6:2 FTOH and PFOS. The EPA recently revised its health advisory for PFOS to state that in effect no level of exposure to it in drinking water is safe. The Inquirer bought pieces of the Phillies artificial turf and had it tested at two labs, and found it contained 16 types of PFAS, including PFOS.
PFAS, or per- and polyfluoroalkyl substances, are a class of about 12,000 chemicals often used to make products resist water, stains and heat. They are called “forever chemicals” because they don’t naturally break down, and are linked to cancer, liver problems, thyroid issues, birth defects, kidney disease, decreased immunity and other serious health problems.
PFAS can be ingested, inhaled and absorbed through the skin – or even enter the body through open wounds.
Phillies ball players competed on artificial turf between 1971 and 2003, and six former Phillies died in their 40s or 50s – about three times the rate of the adult male general population. But researchers noted the age group in which they died is at a higher risk for the disease, and that could skew the results. Experts have said other factors could contribute, like pesticides used on grass fields, chewing tobacco or drug use, or concussions.
Still, the situation highlights the need to study a possible connection between PFAS in turf and cancer, said David Andrews, a senior scientist with the Environmental Working Group non-profit.
“I haven’t seen any direct study trying to quantify how much exposure these players have gotten from playing on artificial turf, and how that compares to other sources of exposure, and that’s the question that will require more investigation,” he said.
Cory Franklin, an internist who researches cancer cases in baseball, told the New York Times in 2017 that Major League Baseball and the players’ union should hire epidemiologists and statisticians to examine the issue, and create a registry of players and their causes of death.
Bennett noted that researchers in China who recently found PFAS in brain tumor tissue wrote: “Our findings suggest that exposure to PFAS might increase the probability to develop glioma [brain tumors].” Italian researchers found PFAS accumulated in the brains of people who drank PFAS-contaminated water.
While that still does not prove causation, experts say, the issue is likely to fuel further debate over synthetic fields. Proponents say they are easier to maintain than grass fields and are not prone to “flooding”, though they do also require significant maintenance. The product is also increasingly used on playgrounds or as alternatives to lawns in drought-plagued regions.
Some manufacturers have claimed the amount of PFAS used in artificial turf isn’t enough to be dangerous, or that they use “safe” PFAS.
“Independent research has shown time and time again that synthetic turf systems provide many community benefits and continue to meet and exceed regulatory standards for human health, safety and performance,” the Synthetic Turf Council, an industry trade group, previously told the Guardian.
Beyond the chemical exposures, critics say the material also emits high levels of methane, a potent greenhouse gas, and sheds microplastics and other chemicals into waterways.
Artificial turf can act as a heat island, increasing playing field temperatures to as much as 93C (200F). National Football League players pressured the league in 2022 to ban artificial turf because of injuries, and the US national soccer teams will only play on natural grass for the same reason.
At least nine municipalities in Connecticut, California and Massachusetts, including the city of Boston, have begun limiting the use of synthetic fields via bans or moratoriums. Legislatures in Connecticut, Rhode Island and Massachusetts also began considering prohibiting them in recent months, while a ban on non-essential uses of PFAS going into effect in Maine in 2029 could bar the use of artificial turf there.
Bennett said the issue highlights the need for the EPA to ban artificial turf and PFAS.
“Is artificial turf easier? Yeah, you don’t have to mow it but that doesn’t mean it’s right to use it,” she said. “We should not have the ability to destroy our planet or health for convenience.”
