Minnesota is one state that has banned the use of coal tar driveway sealants due to accusations that these substances raise cancer rates, leads to infertility, and inhibits childhood development. The manufacturers are denying these claims as they fight an uphill battle that could be in place for the long-term.
As of now, there has been a number of studies that have proven that exposure to coal tar sealant causes a rise in cancer rates. This has led to the coal tar sealant industry fighting a number of bans at state and local levels, stating that the evidence is biased.
Used as a way to extend the life of pavement while also enhancing its look in parking lots and driveways, the substance contains 35% coal tar pitch. Coal tar pitch is a known carcinogen. This has resulted in Minnesota becoming one of the states that has banned its use. It has also been banned in counties within New York, Maryland, Texas, Washington, Illinois, and Washington D.C. Big name hardware stores also topped carrying the toxic substance.
As for where the danger lies, it occurs when there is a breakdown in the sealant, which forms dust that is washed into storm drains by rain, tracked into office buildings and homes on the bottom of shoes, and is even blown onto food supplies. The Chicago Tribune reported that the dust can be inhaled by animals and people that are in close proximity to a surface that has been sealed by the substance.
The most toxic chemical in the mix is polycyclic aromatic hydrocarbons. This has been linked to cancer, but has also been linked to infertility and inhibited childhood development. This has led to people and businesses using alternative driveway coatings to seal the concrete. These other coatings consist of polymers and other substances that are deemed harmless to people and animals. They also do not break down to where parts of them are washed away into the water supply.
As for coal tar driveway sealants, they have been used for years to give asphalt a specific sheen and to extend the life of the surface. It requires re-application every couple of years.
Despite this mounting evidence that suggests there is a risk, the industry has been fighting against the bans over a number of years. The success that they have had is due to studies the industry has funded to declare industrial pollution and vehicle exhaust as the main sources of polycyclic aromatic hydrocarbons. These studies also assert that dandruff shampoos contain 12.5 percent of coal tar with cosmetics, medicines, and plastics also containing it.
A number of reports released in 2012 by the USGS disproved the findings of the industry-funded studies. This in itself proved that the evidence for banning coal tar sealants is mounting.