Carbon Monoxide Risks: Why Chimney Maintenance Matters

Published February 23, 2026

Carbon monoxide (CO) is colorless, odorless, and tasteless. You cannot see it, smell it, or taste it. Yet it kills more than 400 Americans every year and sends over 50,000 to emergency rooms, according to the Centers for Disease Control and Prevention. For homeowners in Northern New Jersey who rely on fireplaces, wood stoves, and gas heating during our cold winters, understanding the connection between chimney maintenance and carbon monoxide safety is critical.

How Chimneys Prevent Carbon Monoxide Exposure

When you burn any fuel, whether wood, gas, or oil, the combustion process produces carbon monoxide as a byproduct. Your chimney's job is to safely channel these combustion gases, including CO, out of your home and into the outside air. The system works through a combination of draft (the natural upward flow of hot gases), a properly sized and intact flue liner, and an unobstructed vent path from your appliance to the top of the chimney.

When any part of this system fails, carbon monoxide can enter your living space instead of exiting through the chimney.

Common Chimney Problems That Cause CO Exposure

Blocked Flues

Animal nests, leaves, debris, and excessive creosote buildup can partially or completely block your chimney flue. When the flue is blocked, combustion gases have nowhere to go but back into your home. This is one of the most common causes of CO exposure from chimneys.

Cracked Flue Liners

The flue liner is your primary barrier between combustion gases and your home's interior walls. When the liner cracks, which happens frequently in NJ due to freeze-thaw cycling, carbon monoxide can seep through the gaps and into adjacent rooms. This type of leak is particularly dangerous because it often goes undetected for long periods.

Damaged or Stuck Dampers

A damper that will not open fully restricts the flow of exhaust gases. If you light a fire with a partially closed damper, smoke and CO will enter your living space. Rust, warping, and debris accumulation are common causes of damper malfunction in NJ homes.

Negative Pressure

Modern, tightly sealed homes can create negative pressure that fights against the natural updraft of your chimney. This can pull carbon monoxide down the chimney and into your home, especially if exhaust fans, dryers, or HVAC systems are running simultaneously. Proper chimney sizing and ventilation help prevent this issue.

Symptoms of Carbon Monoxide Poisoning

Because CO is undetectable by human senses, knowing the symptoms is vital:

• Headache (the most common early symptom)
• Dizziness and lightheadedness
• Nausea and vomiting
• Confusion and disorientation
• Weakness and fatigue
• Chest pain
• Blurred vision

If multiple family members experience these symptoms simultaneously, especially during fireplace or heater use, evacuate immediately and call 911.

How Chimney Maintenance Prevents CO Exposure

• Annual inspections identify cracked liners, blockages, and damper problems before they become dangerous
• Regular cleaning removes creosote and debris that can obstruct the flue
• Chimney cap installation prevents animal nests and debris from blocking the flue
• Timely repairs fix cracks, gaps, and structural damage that allow CO to leak into your home
• Proper relining ensures a continuous, sealed pathway for exhaust gases

Additional Safety Measures

In addition to proper chimney maintenance, every NJ home should have:

• CO detectors on every level and near sleeping areas (required by NJ law)
• Working batteries in all CO detectors (test monthly)
• A fire extinguisher near the fireplace
• Never use a generator, grill, or camp stove indoors