What environmental hazard is a product of the natural decay of radioactive substances found in the ground?

Radon is a naturally occurring radioactive gas that results from the decay of uranium and radium found in soil, rock, and water. It can seep into homes through cracks in floors, walls, and foundations, especially in areas with significant geological deposits.

As a colorless, odorless gas, radon is particularly dangerous because it is difficult to detect without specialized equipment. Long-term exposure to radon is linked to an increased risk of lung cancer, making it a noteworthy environmental hazard in real estate. Property owners in areas prone to high radon levels are often encouraged to conduct testing and, if necessary, take mitigation steps to reduce radon concentrations within their homes.

The other options—such as asbestos, which is a fibrous mineral linked to lung diseases, including cancer; lead, a toxic metal historically found in paints; and carbon monoxide, a colorless gas produced by burning fossil fuels—are hazardous in different contexts but do not originate from the natural decay of radioactive materials in the ground like radon does.