There is a hidden and longer term health issue with certain types of driveway sealant – they break down over time from cars being driven on them and from weathering.  If the driveway sealant is made from coal tar, this break down can release chemicals called polycyclic aromatic hydrocarbons (PAHs).  These chemicals are carcinogenic and are already in the environment as part of air pollution.  However the additional amount from driveway sealant can produce local contamination that can be a health concern.  The United States Geological Survey (USGS) has shown that the dust on parking lots and driveways sealed with coal tar-based products can be high in PAHs.  Of further concern is their finding that this contamination can extend into nearby homes and create high levels of carcinogenic PAHs in house dust.  Fortunately, asphalt-based driveway sealant is an alternative to coal tar products.  It coats well and does not contain PAHs making the asphalt product safer and better for the environment.  

Follow these simple steps to decrease your family’s exposure to this source of PAHs:

1. Choose asphalt-based instead of coal-tar based sealants when coating your driveway or parking areas;
2. If the driveway and parking areas will be sealed by your landlord or a property manager, tell them about the issues with coal tar and ask that they instead choose asphalt-based products; 
3. Keep indoor floors clean with frequent wet mopping and vacuuming to decrease the amount of potentially contaminated house dust that young children may come in contact with.

For further information:

• Driveway Sealants Overview
• CT Environmental Health Technical Brief: Coal Tar Driveway Sealant
• Polycyclic Aromatic Hydrocarbons (PAHs) & Coal-Tar-Based Pavement Sealcoat (US Geological Survey)
• Circular Letter 2016-49 Important Reminder Regarding Coal Tar Sealants for Road Repair