DANBURY, Conn.—Rubber mulch once again has become the subject of controversy with the publication of a recent column in the Danbury News-Times calling for a ban on the material as playground surfacing.
Eileen Fitzgerald, a columnist for the News-Times, cited several authorities in urging an end to scrap-tire-based playground surfacing, including a 2008 study from a Connecticut-based non-profit organization and a book by a horticulture professor at Washington State University.
The Rubber Manufacturers Association (RMA), however, cited its own and other studies demonstrating the safety and efficacy of rubber mulch, and said that studies claiming the contrary are scientifically invalid.
“As schools and town officials build or improve playgrounds for toddlers, rubber mulch created from tires has become a product of choice by some because it is soft and affordable,” Ms. Fitzgerald wrote in her Jan. 22 column. “That needs to change.”
According to Ms. Fitz-gerald, scientific evidence shows that ground rubber mulch leaches heavy metals into the ground and groundwater, potentially causing organ and neurological damage, cancer and mutations.
“This clearly is a case where parents must protect their children until the country's regulating authorities address the issue,” she wrote.
In her column, she quotes a story in which Grassroots Environmental Education's Doug Wood, of New York, reportedly said: “Tires are so full of toxic chemicals they have to be disposed of in a special landfill. So why would you grind them up and put them on a field where kids are going to play?”
Among other sources, Ms. Fitzgerald cited the 2008 study performed by North Haven, Conn.-based Environment & Human Health Inc. (EHHI)
The EHHI study, reported in a 2008 story in Tire Business, was the impetus for a bill before the New York General Assembly calling for a six-month moratorium on the use of rubber playground mulch. The study also caused several other state legislatures to consider enacting such a moratorium or placing other limits on recycled rubber turf.
Ms. Fitzgerald cited EHHI's research on rubber tire mulch, noting that in one set of experiments, “the organization tested the chemicals released from the tire crumbs used for playground 'in-fill' and commercial rubber mulch. Ten metals were leached from the samples of tire crumbs and tire mulch in the first experiment.
“In the second experiment, 25 chemical species were identified, with 72 percent to 99 percent certainty in the mass spectrometry and gas chromatography analysis. Nineteen chemicals were identified with more than 90 percent certainty and five with more than 98 percent certainty.”
According to the organization, “it is clear that the recycled rubber crumbs are not inert, nor is a high-temperature or severe solvent extraction needed to release metals, volatile organic compounds or semi-volatile organic compounds.”
Ms. Fitzgerald also pointed to the work of Linda Chalker-Scott, extension horticulturalist and associate professor at Washington State University's Puyallup Research and Extension Center.
Ms. Chalker-Scott had a chapter, “The Myth of Rubberized Landscapes,” in her 2010 book, The Informed Gardener Blooms Again.
In that chapter, Ms. Chalker-Scott condemned rubber mulch as both highly flammable and inferior to wood chips in controlling weeds.
“Far from being permanent, rubber is broken down by microbes like any other organic product,” she wrote. She cited research at Bucknell University showing that rubber leachate from tires can kill fish, algae, and other living organisms in aquatic communities.
“It is abundantly clear from the scientific literature that rubber should not be used as a landscape amendment or mulch,” Ms. Chalker-Scott wrote. “There is no question that toxic substances leach from rubber as it degrades, contaminating the soil, landscape plants and assorted aquatic systems.”
Ms. Fitzgerald closed her column by warning: “This clearly is a case where parents must protect their children until the country's regulating authorities address the issue.”
However, RMA Vice President Michael Blumenthal insists the preponderance of the scientific evidence points in the other direction. “If you look at EHHI's report, one of their conclusions is that more research is necessary,” he told Tire Business. He addressed only the EHHI study, not Bucknell's research or Ms. Chalker-Scott's book.
“If you read between the lines, EHHI wants more funding for further research,” Mr. Blumenthal said. “I think what they're doing is self-serving. All their findings are invalid—I told them this, on the air over National Public Radio.”
RMA's most recent study on rubber mulch was performed for the association by Pittsburgh-based Cardno ChemRisk and issued in August 2013.
A systematic review of the existing scientific literature on rubber mulch, Cardno ChemRisk said, shows that no adverse human or ecological health effects are likely to result from the use of rubber mulch. However, it agreed that more research is needed to address uncertainties.
“Although unique or significant health risks are unlikely from use of recycled tires in sports or playing fields, research to affirm the continued safety of these products is planned and ongoing,” it said.
Mr. Blumenthal said more than 120 scientific reports have affirmed the safety of rubber mulch, including studies from the U.S. Environmental Protection Agency; several states, including California; and several European countries, including France, Italy and the Netherlands.
Nevertheless, controversy over rubber mulch is bound to continue, according to Mr. Blumenthal.
“This is not the first time, and it won't be the last,” he said. “The market is pretty much split into two camps: those who accept the use of ground rubber, and those who don't.
Opponents of rubber mulch, Mr. Blumenthal said, reminded him of an old saying: “When you have facts, you pound the facts. When you have no facts, you pound the table.”
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