Officials Ban Coal Tar Sealants


San Antonio has become the latest U.S. city to prohibit the use of coal tar-based sealants on projects throughout the area.

Coal tar-based sealcoat products, commonly used in the paving of driveways, parking lots and roadways, contain chemicals known to cause cancer, according to research by federal officials.

These health concerns fueled City Councilman Ron Nirenberg’s 2014 appeal that city officials consider banning the product, the City of San Antonio said in an announcement.

“This is a major win for public health,” Councilman Nirenberg said when the ordinance passed.

“We know that coal tar-based sealants pose a risk to human health and can seep into waterways over time through stormwater runoff,” he added. “This is a long-overdue measure that is based in common sense and backed by science.”

The restrictions of this ordinance apply to coal tar sealant products in the city and do not affect the use of asphalt-based sealer products, city officials clarified.

The ban will go into effect Jan. 1, 2017, to allow affected industries an opportunity to adjust their operations and comply with these policies.

The ban only applies to future use, a local news station explained.

Path to Prohibition

San Antonio’s prohibition of the products follows similar actions by Minnesota and Washington legislatures, which banned the product within state lines in 2013.

Within the state of Texas, the Edwards Aquifer Authority has adopted a ban of coal tar sealants over environmentally sensitive portions of Hays and Comal counties, the city noted.

Austin banned the use and sale of coal tar sealants in 2005, and San Marcos unanimously approved a ban in May.

seal coat application
Barbara Mahler, USGS

Studies indicate that coal tar sealants are a major source of polycyclic aromatic hydrocarbons or PAHs, which are known to be toxic, especially at high levels of exposure.

Bans have also been instated in New York, Wisconsin, the District of Columbia and Annapolis, MD.

“Just like we removed lead paint from schools—that there's this substance that is harmful, it’s toxic, will no longer be used in the city of San Antonio,” Nirenberg said. “And that's a very good thing.”

A Foundation for Concern

San Antonio city staff reviewed and analyzed more than 80 white papers, independent studies and articles published by universities, independent researchers, the National Oceanic and Atmospheric Administration and the Environmental Protection Agency in defining the ordinance, it said.

Those resources indicated that coal tar sealants are a major source of polycyclic aromatic hydrocarbons, or PAHs. These chemicals, especially at high levels of exposure, are known to be toxic, officials explained.

“When you live near this area or when you work spraying these materials on the ground, you are exposed to higher levels of those contaminants,” Ana Sandoval, of the Air and Health Collaborative, told station KSAT 12.

In 2015, two studies by the U.S. Geological Survey determined that runoff from pavement seal-coated with coal tar is toxic to aquatic life and has detrimental effects on DNA.

An estimated 85 million gallons of coal-tar-based sealant are applied to pavement each year, primarily east of the Continental Divide in the U.S. and parts of Canada, according to the USGS.

Coal-tar sealants have “significantly” higher levels of PAHs and related compounds compared to asphalt-based pavement sealants and other urban sources, such as vehicle emissions and used motor oil, according to the USGS.


Despite the findings of university, federal and independent research, there are those who disagree with the ban.

Anne LeHuray, of the Pavement Coatings Technology Council, claims that many environmental organizations don't classify the sealants as hazardous, according to KHOU.

“There's no data indicating that there has been a problem. There's no problem now and there's no anticipation that there will be a problem,” she said.

newley sealcoated parking lot
Peter Van Metre, USGS

The restrictions of this ordinance, which go into effect Jan. 1, 2017, apply to coal tar sealant products in the City of San Antonio and do not affect the use of asphalt-based sealer products.

LeHuray also touts the performance benefits of the coal-tar sealants.

“It is still is the fact that the coal-tar based product lasts longer, protects better, and is a proven product,” she told KSAT.

The most common alternative to coal tar-based sealants is an asphalt-based sealant, which LeHuray said does not protect as well as coal tar.

"If people want to use alternative products, allow them. But to restrict people to just a single product without having a choice—for no environmental or health based benefit—doesn’t seem to make much sense to us," she added.

Moreover, she told Texas Public Radio, coal tar sealants are often used because it can be applied in cold weather, unlike other products.

“So, the continuity of the business in terms of keeping their people from season to season will be impacted and people will only be working nine to 10 months out of the year,” she said.

Two city councilmen voted against the ban, also citing concerns that it will negatively affect small businesses.

According to KHOU, local business owners worry that the ban on coal tar sealants will lead to higher prices for alternative sealants and also lead to more frequent closures of their parking lots if the alternatives don't last as long.

Additionally, violations of the ordinance will reportedly carry fines that could reach $2,000 a day.


Tagged categories: Asphalt; Coal tar epoxy; Coatings Technology; Government; Health and safety; North America; Regulations; Research; Sealant; Toxicity

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