How Does Radon Cause Cancer? What Every Homeowner Should Know

By Quality Environmental Testing (QET) | Serving Lockport and the Chicagoland Area Since 2002

Most homeowners know that radon is the second leading cause of lung cancer after smoking. But one of the questions we hear most often during radon inspections is:

"How does a naturally occurring gas actually cause cancer?"

The answer isn't always straightforward, but understanding how radon affects your lungs helps explain why professional testing is so important.

At Quality Environmental Testing (QET), we've tested homes throughout Lockport, Lemont, Homer Glen, New Lenox, Frankfort, and the surrounding communities for more than two decades. One thing we've learned is that you can't predict a home's radon level by its age, appearance, or neighborhood. We've tested brand-new homes with elevated radon and older homes with very low levels.

That's why understanding the science—and testing your home—is so important.

What Happens When You Breathe Radon?

Radon is a naturally occurring radioactive gas released as uranium in the soil slowly breaks down.

Because it has no color, odor, or taste, people can breathe elevated radon levels for years without ever knowing it's present.

When radon is inhaled, the gas itself usually passes back out of your lungs. The greater concern comes from what happens next.

As radon decays, it produces tiny radioactive particles called radon decay products (sometimes called "radon daughters"). These particles can attach to dust and other airborne particles inside your home.

When they're inhaled, they may become trapped inside your lungs.

How Radon Damages Lung Cells

Those trapped particles continue to release alpha radiation.

Alpha particles cannot travel very far and cannot pass through your skin, but inside the lungs they release their energy directly into nearby cells.

Over many years, repeated exposure may damage DNA inside lung cells.

Most damaged cells repair themselves or die naturally.

Occasionally, however, a damaged cell survives with permanent genetic changes. If enough mutations accumulate over time, that cell can eventually become cancerous.

This process doesn't happen overnight.

For most people, the concern comes from long-term exposure over many years, which is why testing and reducing elevated radon levels early is so important.

Why Radon Is More Dangerous Indoors

Outdoors, radon quickly disperses into the atmosphere.

Inside a home, it's different.

Radon enters through:

• Foundation cracks

• Sump pits

• Utility penetrations

• Crawl spaces

• Expansion joints

• Concrete floor openings

Modern homes are built to conserve energy, which also means they retain indoor air more effectively.

During winter months especially, homes are often sealed tightly, allowing radon concentrations to build.

This is one reason we frequently recommend professional testing during real estate transactions and after major renovations.

What We See During Professional Radon Testing

One of the biggest misconceptions we hear is:

"My neighbor's house tested low, so mine should too."

Unfortunately, that isn't how radon works.

We've tested neighboring homes where one measured well below the EPA action level while the house next door measured significantly higher.

We've also found elevated radon levels in:

• Brand-new construction

• Recently remodeled homes

• Homes with finished basements

• Homes without basements

• Homes that had never shown any obvious warning signs

There is simply no reliable way to predict radon levels without testing.

Understanding Radon Measurements

Radon is measured in picocuries per liter (pCi/L).

The U.S. Environmental Protection Agency recommends taking action if long-term radon levels reach 4.0 pCi/L or higher.

However, the EPA also emphasizes that there is no completely safe level of radon exposure. Because any exposure carries some risk, many homeowners choose to reduce radon levels even when results fall between 2.0 and 4.0 pCi/L, especially if young children, smokers, or individuals with existing lung conditions live in the home.

The lower the radon level, the lower the lifetime risk.

Is Radon the Only Source of Radiation?

No.

Every day we're exposed to small amounts of natural background radiation from:

• Sunlight

• Cosmic radiation

• Rocks and soil

• Certain foods

• Naturally occurring radioactive materials

What makes radon different is that it can become concentrated inside homes where people spend many hours each day.

According to the EPA, radon exposure is the second leading cause of lung cancer overall and the leading cause among people who have never smoked.

Can Radon Cause Cancer in Everyone?

No.

Cancer risk depends on several factors, including:

• Radon concentration

• Length of exposure

• Smoking history

• Individual genetics

• Overall lung health

Smokers face a much greater risk because smoking and radon work together to dramatically increase the likelihood of developing lung cancer.

But even people who have never smoked can develop radon-related lung cancer.

How Can You Protect Your Family?

The good news is that radon is both measurable and correctable.

If elevated levels are found:

1. Confirm the results with professional testing if needed.

2. Install a mitigation system if recommended.

3. Retest to verify the system is working properly.

Most mitigation systems reduce radon levels significantly, providing long-term protection for your family.

Why Professional Radon Testing Matters

At Quality Environmental Testing (QET), we use calibrated continuous radon monitors that provide hourly measurements throughout the test period.

Unlike many DIY kits, professional testing offers:

• Accurate continuous monitoring

• Proper placement following EPA protocols

• Detailed electronic reports

• Results accepted for most real estate transactions

• Independent testing with no conflict of interest

Because we perform testing only and do not install mitigation systems, our recommendations remain completely unbiased.

Frequently Asked Questions

How does Radon cause cancer?

When radon gas is inhaled, it breaks down into tiny radioactive particles that can become trapped in your lungs. These particles release energy that can damage lung cell DNA over time. With years of exposure, that damage can increase the risk of developing lung cancer.

Can I smell or taste radon?

No. Radon is completely odorless, colorless, and tasteless.

Should I test if my neighbor already did?

Yes. Radon levels can vary dramatically between neighboring homes.

Is radon only found in older homes?

No. We've found elevated radon levels in both older homes and brand-new construction.

How often should I test?

The EPA recommends testing every home at least once and retesting after major renovations, changes to the HVAC system, or after installing a mitigation system.

Schedule Professional Radon Testing

Radon is one of the few serious indoor air hazards that can be accurately measured and effectively reduced.

If you live in Lockport, Lemont, Homer Glen, New Lenox, Frankfort, or the surrounding Chicagoland area, Quality Environmental Testing (QET) provides professional, independent radon testing using calibrated continuous radon monitors.

Knowing your radon level is the first step toward protecting your home and your family's health.