Which contaminant is drawn into buildings from soil and is a known carcinogen?

• A. CO
• B. Radon
• C. VOCs
• D. SVOCs

Answer: (B)

Radon is the contaminant described here. It’s a naturally occurring radioactive gas produced by uranium in soil. It moves through soil and into buildings when there are openings in foundations, crawl spaces, or through cracks, driven by pressure differences between indoors and outdoors. Once inside, radon can accumulate to higher concentrations, and long-term exposure is a known cause of lung cancer, making it a primary carcinogen associated with soil-to-building transfer.

The other options don’t fit this scenario as cleanly. Carbon monoxide comes from combustion processes and enters indoor air primarily through faulty appliances or exhausts, not from soil seepage. VOCs and SVOCs are organic compounds that can off-gas from building materials, furnishings, or consumer products, rather than being drawn in from the soil itself.