Parking lot sealant ups cancer risk
Posted on 20 January 2010 | by Robert McClure, Investigate West | 
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Chemicals in a cancer-causing substance used to seal pavement, parking lots and driveways across the U.S. are showing up at alarming levels in dust in American homes, prompting concerns about the potential health effects of long-term exposure, a new study shows.
The substance is coal tar sealant, a waste product of steel manufacturing that is used to protect pavement and asphalt against cracking and water damage, and to impart a nice dark sheen. It is applied most heavily east of the Rockies but is used in all 50 states.
But scientists with the U.S. Geological Survey say the sealant — one of two types commonly used in the U.S. — doesn’t stay put. It slowly wears off and is tracked into homes on the shoes of residents.
The USGS study, which found high levels of chemicals used in the sealant in house dust, marks the first time researchers have raised alarms about potential health effects for humans — especially young children — from the parking-lot coatings.
Taken with previous studies indicating that the chemicals contaminate waterways, where they have been shown to harm insects and tadpoles, it raises serious questions about the advisability of using coal tar as a sealant, the scientists say.
“This is the kind of thing where, when you give a presentation, people’s eyes get big — even scientists,” said Barbara Mahler, a USGS hydrologist who directed the latest research.
The scientists’ published their research Jan. 11 in the science journal Environmental Science & Technology. The research focused on a class of chemicals known as polycyclic aromatic hydrocarbons, or PAHs, which are a significant component of coal tar. The research examined both parking lot dust and dust tracked into homes.
A known carcinogen
Coal tar is known to cause cancer in humans. That finding dates to the 1770s, when chimney sweeps in London were found to have high levels of scrotal cancer. Late the next century, it was associated with skin cancers among creosote workers. PAHs themselves are listed by the U.S. Environmental Protection Agency as a probable human carcinogen, based on laboratory studies in which they caused cancer in animals.
Emerging evidence also suggests that babies exposed to PAHs while in the womb may be more prone to asthma and other ailments, and may have lowered IQs.
The new USGS study compared house dust from 23 ground-floor apartments in Austin — 11 with coal tar-sealed parking lots and 12 coated with other substances, or not sealed at all. The study found that dust in the apartments next to the coal-tar-sealed lots had PAH pollution levels 25 times higher, on average, than the other lots.
Coal tar sealant “is used in all 50 states” — maybe, but is banned here in the District of Columbia since last year. There's a $2,500 per day fine if you use it: http://ddoe.dc.gov/ddoe/cwp/view,A,1209,Q,50053....
nice story, robert — jay
Thanks for sharing this info, dcjay.
Do you know if the sealcoat ban in the District was a result of citizen advocacy or an ordinance crafted from within by a council member?
I don't know — probably both. Now the D.C. city council is considering a bill that would ban a host of chemicals, including bpa. These actions can be significant because we don't have a state or state legislature; that role is filled here by the city council.
Thanks for the heads up. Sounds like folks concerned about coal tar and polycyclic aromatic hydrocarbons should be keeping an eye on the D.C. City Council for pointers on how to proceed with banning or regulating these carcinogens in their own communities.
The story that Mr. McClure wrote was filled with so many glaring errors and is so one sided, it leaves me speechless. I really am at a loss as to where to start.
I am curious to know if Mr.McClure actually researched to see if there was another viewpoint to this story?
I wonder if Mr. McClure asked USGS how they distinguished PAH from sealer products vs. the thousand of other sources of PAHs (natural or combustion related)? Did Mr. McClure happen to mention that the study with the children was the first of its kind. I don't think so. Did Mr. McClure happen to mention that a typical person ingests PAHs on a daily basis? I wonder if Mr McClure mentioned that combustion related sources are the largest contributor to PAHs in the environment?
I am curious to know if Mr. McClure was perhaps motivated to write such a sensational story to help get his new venture Investigate West off the ground?
I would like to assist Mr. McClure if I may. For those who are wondering if there is an opposing viewpoint, go to http://www.truthaboutcoaltar.com/.
Tar sealants are not used in all 50 states. Another error by Mr. McClure.
The DC ban was a sham and a joke. DC paid for a study and they found that sealer was not a major source of PAHs, but they banned it anyway. Why did they waste all that money on the study.
Sealers are not the problem. Combustion sources are. I kind of doubt that DC will be banning cars anytime soon.
Mr. McClure – You did a wonderful job presenting the argument. Lance65 is nothing more than a lobbiest for coal tar, lining her own pockets (Anne LeHuray) to promote this toxic waste. An army is mounting against the coal tar seal coat industry and they are on their way out the door.
Approve.
Wendy Norris
Investigative reporter. Freelance muckraker. Rabble-rousing editor.
mobile: 970-222-8409
web: http://www.westerncitizen.com
social media: card.ly/wendynorris | contxts wendynorris to 50500
Approve.
Wendy Norris
Investigative reporter. Freelance muckraker. Rabble-rousing editor.
mobile: 970-222-8409
web: http://www.westerncitizen.com
social media: card.ly/wendynorris | contxts wendynorris to 50500