radon in attached houses 2

https://yorkparadonguidesource.clearminster.com/posts/your-complete-york-pa-radon-guide-testing-mitigation-and-home-safety

Radon in attached houses is a concern because the gas can seep through shared walls and foundations. Since attached homes often have basements or crawl spaces, radon levels can vary between units. Testing each unit is important to ensure everyone is safe from this natural radioactive gas.