When officials in suburban Des Plaines, Ill., read about the hazards of spreading cancer-causing coal tar on playgrounds, parking lots and driveways, they moved to join other communities across the nation that have banned pavement sealants made with the industrial byproduct.
But the coal tar industry was ready for a fight.
After Austin, Texas, in 2005 became the first U.S. city to ban coal tar sealants, industry leaders formed a tax-exempt lobbying group and started funding their own research -- all in an effort to convince homeowners and elected officials that coal tar sealants are safe.
"My members don't want to sell a product that causes harm," Anne LeHuray, executive director of the Pavement Coatings Technology Council, the industry lobbying group, said.
The industry's efforts have worked in some cases. Since 2010, cities including Des Plaines and Springfield, Mo., and the states of Illinois, Michigan and Maryland have rejected coal tar-related legislation after Ms. LeHuray and local contractors intervened.
"It seemed too confusing," said Patricia Haugeberg, a Des Plaines alderman who moved to table the suburb's proposed 2011 ban.
In a February presentation to contractors, a top industry representative boasted that they are beating government scientists "on their own turf."
Yet a Chicago Tribune review of the two industry-funded studies published in a peer-reviewed scientific journal in recent years found they fall short of proving their authors' contention that coal tar sealants pose few, if any, threats to human health and wildlife.
Manufacturers promote coal tar pavement sealants as a way to extend the life of asphalt and brighten it every few years with a fresh black sheen. The products are most commonly used in states east of the Continental Divide; in the West, contractors tend to use asphalt-based sealants that contain significantly lower levels of worrisome chemicals.
Coal tar sealants contain up to 35 percent coal tar pitch, partially refined waste from steelmaking that the National Toxicology Program and the International Agency for Research on Cancer consider a known carcinogen. Among the chemicals of concern in the products are polycyclic aromatic hydrocarbons, or PAHs, which not only pose a cancer risk but can trigger developmental problems and impair fertility, according to the U.S. Environmental Protection Agency.
Peer-reviewed studies by government scientists have found that coal tar sealants are a major source, and sometimes the dominant source, of PAH contamination in urban areas. Other sources of the chemicals include vehicle exhaust and factory emissions.
In response to the growing body of federal research and regulatory pressures, the coal tar industry turned to a pair of consulting firms frequently hired by corporations dealing with environmental, health or safety issues -- Exponent Inc. and Environ International. The industry-funded papers, published in a minor journal called Environmental Forensics, contend that coal tar sealants are at best a minor source of pollution.
Kirk O'Reilly, an Exponent senior scientist and the study's chief author, said government researchers have overstated their conclusions and failed to consider "the large body of literature" about the chemicals. The government research, Mr. O'Reilly said in email response to questions, "does not prove that sealers are a source."
But at the end of his paper, he acknowledges that coal tar sealants "cannot be eliminated as a PAH source."
New research from Baylor University adds to the troubling picture. The study, published in January in the peer-reviewed journal Environmental Science and Technology, found that exposure to coal tar-contaminated dust during the first six years of life significantly increases the risk of developing cancer.
A month after the study came out, the industry lobbying group hosted an hourlong Web presentation that promised to teach contractors "how you can be successful in defense and what to say to customers, media, and even state and local officials who have questions about the lifeblood of your business." One of the sponsors was Koppers Inc., a Pittsburgh-based company that processes coal tar at a plant in west suburban Stickney, Ill.
Mike Juba, a Koppers health and safety official, urged contractors to stress the industry-funded science in conversations with customers. He also advised them to talk about their contributions to local economies.
"To eliminate a useful product and put the businesses and jobs of real people at risk hurts more people than it helps," Mr. Juba said during the presentation. Koppers and Mr. Juba did not return calls seeking comment.