radon gas risk

https://getradonfaninstallationhaven.dovetailscope.com/posts/what-to-expect-during-a-radon-fan-installation

You might not realize it, but radon gas is a naturally occurring radioactive threat that can seep silently into your home from the ground, building up in basements and lower floors without any smell or color. Long-term exposure is a leading cause of lung cancer, second only to smoking, making testing and mitigation essential for homes in affected areas.