A new study reveals that known carcinogens are being used in popular parking lot and driveway sealants used across the nation, and that these chemicals have leaked into our homes and the environment. InvestigateWest reports these cancer-causing substances, in the form of dust, are showing up at alarming levels in homes. This is the first time researchers have raised alarms about potential health effects of long-term exposure for adults and young children from the parking lot coatings. 

The culprit is coal tar sealant, a waste product of steel manufacturing used to protect pavement and asphalt against cracking and water damage. It is also what gives parking lots their nice, dark sheen. It is most commonly used by contractors in the eastern part of the United States, though it can be found everywhere.

Further, this study from the U.S. Geological Survey reveals that the sealant doesn’t stay on driveways and roads. Among other means of transport, it seeps into waterways and gets tracked into homes. Most disturbing, the study found high levels of sealant chemicals in house dust.

The study focuses on a class of chemicals known as polycyclic aromatic hydrocarbons, or PAHs, which are a significant component of coal tar. PAHs are known to harm insects and tadpoles once they get into waterways. Significantly, PAHs have been proven cause cancer in humans. MSNBC.com reports that this cancer connection dates back to the 1770s, when chimney sweeps in London were found to have high levels of scrotal cancer. New evidence suggests that babies exposed to PAHs while in the womb may have lower IQs, as well as being more prone to asthma and other ailments.

What’s more, young children are especially vulnerable. Children have a higher metabolic rate and their organs are still developing. As scientists point out, they play on or near floors where carpets concentrate and retain toxics. Stanford University researchers have reported children putting their hands on contaminated surfaces and then into their mouths up to 60 times an hour.

Luckily, changes in regulations are in the works. Ted Schettler is a science director of the Collaborative on Health and the Environment, a group of medical professionals trying to reduce environment-related diseases. He points out that the new research on parking lots is important because scientists have been trying to pinpoint the exact source of PAHs for years.

Rep. Lloyd Doggett (D-Texas) has called for a nationwide ban of the coal tar pavement sealants, which are applied by big contractors as well as operators with little more than a truck and a spray tank. As Doggett said in a written statement, “I am pleased my repeated efforts have resulted in the EPA now initiating this long-overdue work, and we might finally move toward a nationwide ban on this dangerous substance.”