Growing up, my mom had a note scotch-taped to the back door of our house: “Shoes off! Love, Mom” it read in her signature cursive. My brothers and I thought the rule was crazy and ignored it more than we should have.
Twenty years later, I am a notorious no-shoes-in-the-house person. I don’t like the idea of street germs coming indoors. Some people balk at the request (mostly my family and boyfriend), but if you’ve ever stepped in a dirty puddle or have dogs that live in your area, you may understand.
A new study finds that our shoes may be bringing a lot more than bacteria into our homes. Before the study, conducted by the U.S. Geological Survey, researchers weren’t exactly sure how certain carcinogens were landing in household dust.
The study found that the dust inside homes with coal-tar sealed surfaces outside had 25 times higher levels of the cancer-causing chemical, polycyclic aromatic hydrocarbons (PAHs), than those without it. Coal-tar sealant is what gives many driveways and sidewalks their smooth, (tar) black finish and protects against cracking. Over time, the sealant wears off and is tracked into our homes on our shoes.
Though it may be widely used, coal tar is a known carcinogen. Researchers say that asphalt or concrete is a better choice than coal tar, which has 1,000 times the levels of PAHs.
And because the world is full of coal-tar lots and countless other germs…shoes off is, in fact, a good practice!