Carbon Monoxide Safety: What To Do, What To Watch For, and How To Prevent Exposure

SilentShadow publishes carbon monoxide (CO) safety information and practical checklists for everyday situations at home, in rentals, and while traveling. Our guides focus on clear action steps, common CO sources, detector basics, and links to official references.

Since 2004, SilentShadow has provided straightforward, scenario-based carbon monoxide safety guides written for real people — not technicians or first responders. Whether you need to know what to do when a CO alarm goes off at 3 a.m., how to choose and place detectors, what symptoms to watch for after an incident, or how to make your home safer before winter, our guides break down each topic into clear steps backed by official sources from the CDC, EPA, CPSC, and other public health agencies.

If your CO alarm sounds or you suspect carbon monoxide:

Move everyone to fresh air immediately (including pets).
Call local emergency services or the fire department for help and air testing.
Do not re-enter the building until professionals confirm it's safe.

Read the step-by-step checklist: What to do if you suspect a carbon monoxide leak.

Start Here

Symptoms

Quick symptom check and when to seek urgent care.

Detect a Leak

Warning signs, common sources, and safe checks.

Prevention

CO detectors, maintenance, ventilation, generator safety.

Long-Term Effects

What recovery can involve and what to monitor.

Sources at Home

Furnaces, water heaters, stoves, garages, generators.

Laws by State

CO detector requirements differ by state and building type.

Not sure where to begin? If you're dealing with an active alarm or symptoms right now, start with the emergency checklist. If you want to understand CO risks before they become urgent, the prevention guide and sources overview are good starting points. For state-specific detector requirements, check the laws by state section.

Start with the Fundamentals

If you're new to carbon monoxide safety, these guides explain the basics and the most common risk scenarios.

CO Detectors & Placement

CO alarms are a key layer of safety, but they work best when installed in the right locations and maintained on schedule. Use alarms that meet recognized standards, follow manufacturer instructions, and keep a simple replacement plan so your devices stay reliable.

CO Detector Laws by State

Carbon monoxide alarm requirements can differ by state, building type, and sometimes by city or county rules. We're building a state-by-state library that summarizes publicly available requirements and links to the relevant statutes and codes, with a clear "Last verified" date.

How We Write

We prioritize official public-health and safety sources and link to primary references where possible.
We separate general education from emergency action steps.
We show update dates and refresh pages that can change over time (especially laws).
This website provides general information only and is not medical or legal advice. If you suspect poisoning, seek urgent medical care.

Frequently Asked Questions

What is carbon monoxide (CO)?

Carbon monoxide is a colorless, odorless gas produced when fuels such as gas, oil, wood, or charcoal burn incompletely. Because you cannot see or smell it, CO is sometimes called the "silent killer." A working CO alarm is the most reliable way to detect it in your home.

What are the first signs of CO poisoning?

Early symptoms often resemble the flu: headache, dizziness, nausea, and fatigue. If several people in the same building feel unwell at the same time — especially if symptoms improve when they step outside — CO exposure should be considered. See our full symptoms guide.

What should I do if I suspect CO?

Move everyone (including pets) to fresh air immediately, call your local emergency number or the fire department, and do not re-enter until a professional confirms the building is safe. Read our step-by-step checklist for more detail.

Where should CO detectors be placed?

Install at least one CO alarm on every level of your home and near each sleeping area. Avoid placing alarms directly next to fuel-burning appliances or in humid areas like bathrooms. See our detector placement guide for room-by-room recommendations.

Can you smell carbon monoxide?

No. Carbon monoxide is completely odorless and colorless. Any unusual smell during a suspected CO event likely comes from other combustion byproducts — not CO itself. A working alarm is the only reliable way to detect it. Learn more in What does carbon monoxide smell like?

Last updated: February 14, 2026