OLYMPIA – Washington became the first state in the nation Thursday to ban toxic asphalt sealants made from cancer-causing industrial waste that have been spread over vast swaths of the nation’s cities and suburbs.
The toxic ingredients in coal tar-based sealants are turning up in ordinary house dust as well as in streams, lakes and other waterways at levels that concern government researchers. The chemicals have been found in people’s driveways at concentrations that could require treatment by moon-suited environmental technicians if detected at similar levels at a toxic-waste cleanup site. The sealants are also applied on playgrounds and parking lots.
When Gov. Christine Gregoire signed the measure Thursday, Washington became the largest government to ban or restrict coal tar asphalt sealants. Last month, Prior Lake, Minn., joined a growing number of local governments to ban them.
Alternative, asphalt-based sealants, shed far fewer toxic particles, government tests show.
The Washington State legislation and a drive for a nationwide ban flowed from studies by the U.S. Geological Survey, which showed that components of the toxic sealants are increasing in many waterways, while levels of most other pollutants are declining. One study of 40 lakes nationwide conducted last year showed high levels of contamination in Lake Ballinger north of Seattle.
A 2009 Geological Survey study identified chemicals associated with the coal tar sealants in house dust at levels that worried researchers because they could contribute to longterm cancer risks, especially in young children who crawl around through – and might accidentally ingest – the toxic dust.
Washington’s move follows earlier bans. The first came in 2006 in Austin, TX, site of the discovery of the link between toxic parking-lot sealants and waterway pollution. Subsequent bans followed in Washington, D.C., and in Madison and surrounding Dane County, Wisconsin.
Washington’s law brings the number of Americans living in places where the coal tar sealants are banned to 8.7 million, according to the Coal Tar Free Americablog by Tom Ennis, an Austin city official who helped prompt research on the sealants.
The fact that a second kind of asphalt sealant without coal tar is widely available helped gain support in the Washington Legislature, said state Rep. David Frockt, D-Seattle, sponsor of the measure (ESHB 1721). Frockt began working on the bill after InvestigateWest reported on the issue last year.
“When I started to understand the science, I concluded there is no reason to have this stuff,” Frockt said. “Nobody felt their business was going to be impacted if they had to go to the (other) sealants.”
In the end, though, “the human health aspect is what really hit home,” Frockt said.
The Pavement Coatings Technology Council, a Washington, D.C.,-area lobbying group representing companies that paint or spray on the deep black coal tar-based sealants, has launched scientific attacks on coal tar research.
The pavement council hired a Seattle-area scientist and consultant who told Washington legislators he found flaws in the methods used by government researchers to produce a “chemical fingerprint.” The Geological Survey researchers say those chemical fingerprints implicate the parking-lot sealants as the largest source in many urban lakes of a class of toxic chemicals known as “polycyclic aromatic hydrocarbons,” or PAHs.
Industry officials’ main defense is that the PAH chemicals can come from a variety of sources other than the coal tar sealants.
“Their mathematical model that purports to apportion sources of PAHs is based on pre-selection of sources using cherry-picked data,” Anne LeHuray, executive director of the Pavement Council, wrote in an e-mail to InvestigateWest.
The new law protects health, saves money and is supported by compelling scientific evidence, said Mo McBroom, a lobbyist for the Washington Environmental Council.
“Dealing with the problem of toxic runoff is huge. This is a big step forward,” McBroom said. “We know that coal tar sealants are potential threats to public health and to water quality.”
The sealants are marketed as a way to extend the life of asphalt, while also restoring a rich dark color. The sealants usually are not applied to public streets.
The alternative to coal tar-based sealants is a class of asphalt-based sealants. Dust on parking lots using the coal tar sealants can contain hundreds or sometimes even thousands of times the concentration of toxic chemicals as dust from parking lots using the asphalt-based products, federal scientists said.
The coal tar-based sealants typically are used more heavily east of the Rocky Mountains in part because coal tar is a waste product of the steelmaking industry that was traditionally based in the Rust Belt. Both coal tar- and asphalt-based sealants have been used in all 50 states.
Coal tar is a known human carcinogen. It caused scrotal cancer in London chimney sweeps in the 1700s and skin cancer in creosote workers in this country a century ago. Children exposed to these chemicals in the womb may be more prone to asthma and other health problems and may suffer from lowered IQs, emerging scientific evidence suggests. In men they can harm sperm and in pregnant women they can cause damage to the umbilical cord.
In streams, the chemicals have been shown to kill tadpoles, cause tumors on fish, stunt growth of aquatic creatures and reduce the number of species able to live in a waterway.
Edited by Rita Hibbard