According to the U.S. Centers of Disease Control and Prevention (CDC ), more than 400 people die in the U.S. from accidental carbon monoxide (CO) poisoning each year. In 2021, over 300 MA residents visited the emergency department (ED) due to accidental CO poisoning. Massachusetts has one of the lowest mortality rates from CO poisoning. However, within the last ten years, there has been an overall increase.
Massachusetts is one of few states that requires CO detectors in every home. On March 21, 2006, Nicole’s Law went into effect requiring CO detectors in all Massachusetts homes with potential sources of CO. The law also sets requirements for the type, location, maintenance, and inspection of CO alarms.
You can use the display to review unintentional CO poisoning hospitalization or ED rates for any city or town in Massachusetts.
What is carbon monoxide?
Carbon monoxide (CO) is a colorless, odorless gas produced from burning fossil fuels, such as gasoline or wood. Unsafe levels of CO can cause sudden illness and death. It claims the lives of hundreds of people every year and makes thousands more ill.
Common sources of exposure include:
Cars
Gas and wood stoves
Clogged chimneys
Unvented kerosene or gas space heaters
Gas water heaters
Gas or oil furnaces
Portable generators
Lawn mowers
Why does MA EPHT track CO poisoning?
We track unintentional CO poisoning to support public health prevention and interventions. CO poisoning data can provide information on when exposures occur. For example, spikes in CO poisoning can happen after disasters and storms. This is often due to increased generator use.
What are symptoms of CO poisoning?
CO poisoning causes a range of symptoms from mild to severe, including death.
The most common symptoms of CO poisoning are:
- Headache
- Dizziness
- Weakness
- Nausea or vomiting
- Trouble thinking
During prolonged exposure or at very high levels, CO can cause loss of consciousness and death.
It is important to note that these symptoms can also point to other illnesses. If a patient complains of these symptoms but does not have a fever, health care providers should consider CO poisoning and collect a detailed history of exposure to CO sources.
What are the sources of CO?
You may be exposed to unsafe levels of CO from:
- Poorly maintained or unvented heating equipment
- Furnaces and water heaters
- Using a gas stove, oven, or grill for heat
- Clogged chimneys or blocked heating exhaust vents
- Snow blocked vents and car pipes
- Running motor vehicles indoors (e.g., in garages or other enclosed spaces)
- Operating generators or gas-powered tools indoors or outside near windows, doors or intake vents
- House or building fires
- Cooking with a charcoal or gas grill inside the home or other enclosed space
- Using a propane camp stove, heater, or light inside a tent
- Engaging in activities near motor vehicle engine exhaust outlets, including boats
CO poisoning during winter months
Most cases of CO poisoning occur during winter in the northern region of the United States. Winter weather or power outages can lead to improper use of heating or cooking devices. These devices can cause CO to build up in a home, garage, or camper and poison the people and animals inside.
Except for space heaters, none of these devices should ever be used inside a home, basement, garage, camper, tent or outside near an open window.
Who is at risk of CO poisoning?
Health
Everyone is at risk of CO poisoning. People living with chronic heart disease, anemia, and respiratory problems can be affected faster than others and may be the first to show symptoms. CO poisoning can also be dangerous during pregnancy increasing the risk of developmental disorders and fetal death.
Age
Infants and children are more susceptible to CO poisoning due to their size. Children left in cars may be at risk, especially in the winter months when snow can block the car’s tailpipe. If you are a caregiver, have your child wait outside the car while you shovel snow.
Older adults often have health conditions that can increase the risk of fatal exposure. Learn more by reading the EPA’s fact sheet on Preventing CO Poisoning in Older Adults.
Environment
Extreme weather due to climate change may cause more flooding and power outages. This can lead to increased use of portable generators and alternate heating sources. Each year, hundreds of deaths and thousands of illnesses occur from CO poisoning from improper indoor use of charcoal or gas grills.
Social determinants of health
Our health is impacted by social determinants of health (SDoH). These are the social, economic, and physical factors where we work, live and play.
Community investments in infrastructure can affect people’s likelihood for experiencing CO poisoning. Areas with higher income often have a greater investment in the electric grid. Areas with powerlines below ground are less likely to have power outages or outages that last a long time. Areas with more trees and poorer housing quality are more likely to have longer power outages or issues with heating.
People who cannot afford to heat their homes, rent, or are experiencing power outages may turn to non-conventional heating sources. This can lead to increased CO poisoning. If you are a landlord, ensure that the heating systems, chimneys, and gas lines are properly maintained. Also, be sure to check for proper ventilation.
Learn more by visiting CDC’s Carbon Monoxide Poisoning page.
How can you prevent CO poisoning?
The release of CO is almost entirely preventable. Make sure devices that may produce CO are correctly installed. Take time to perform maintenance. Make sure the device is operating correctly.
CO poisoning can also be prevented with carbon monoxide detectors. These are also called carbon monoxide alarms. CO detectors are legally required in all Massachusetts' homes with potential sources of CO.
Some steps you can take to reduce your exposure are:
- Install a carbon monoxide alarm in the hallway near every sleeping area in the home.
- Do not heat your home with a gas oven
- Do not use a generator, charcoal grill, camp stove, or other gasoline or charcoal-burning device inside your home, basement, or garage or near a window
- Service heating systems, water heaters, and any other gas, oil, or coal burning appliances by a qualified technician every year
- Call a service expert if you smell an odor from a gas refrigerator. While CO has no odor itself, it could mean there is a defect in the cooling unit which could be giving off CO.
- Buy gas equipment carrying the seal of a national testing agency, such as the American Gas Association or Underwriters' Laboratories
- Check that fuel-burning appliances are properly installed and vented
- Check and clean chimneys every year to be sure they are not blocked by debris
- Ensure idling cars are properly vented, especially in snow
For more prevention tips, visit the Massachusetts Department of Fire Safety’s information on CO Safety and CDC’s CO Prevention Guidelines .
Available data
Use the Explore CO hospitalization poisoning data link on this page to access the following measures:
- Annual number of hospitalizations / ED visits
- Annual crude rate per 100,000 population
- Annual age-adjusted rate per 100,000 population
- Explore data in tables, charts, and maps
MA EPHT presents case counts and crude rates on CO poisoning emergency department and hospital admissions for the following geographies: city/town, county, EP region, EOHHS region, and statewide. Measures are offered by a combination of year, age group, and sex. The most current available data is shown. Be sure to check the site periodically as new data is added. To protect privacy, no information is shown that could potentially identify an individual.
Additional resources
Massachusetts
- MA Department of Fire Services Carbon Monoxide (CO) Safety: General information about carbon monoxide, including safety guides offered in English and Spanish
- MA Department of Fire Services Smoke and Carbon Monoxide Alarms: A quick guide to carbon monoxide and fire alarms offered in English and Spanish
- MA Department of Fire Services Preparing Your Home for a Smoke and CO Alarm Inspection: Information for those selling their home to ensure the CO and smoke alarms meet the requirements for sale or transfer
- Massachusetts Law on Carbon Monoxide Detectors: A list of Massachusetts’ regulations related to carbon monoxide
National
- CDC Carbon Monoxide Poisoning Basics: Information on carbon monoxide from the CDC
- EPA Carbon Monoxide’s Impact on Indoor Air Quality: Information from U.S. EPA on carbon monoxide's impact on indoor air quality